resources/src/mediawiki/mediawiki.js

   1 /**
   2  * Base library for MediaWiki.
   3  *
   4  * Exposed globally as `mediaWiki` with `mw` as shortcut.
   5  *
   6  * @class mw
   7  * @alternateClassName mediaWiki
   8  * @singleton
   9  */
  10 /*jshint latedef:false */
  11 ( function ( $ ) {
  12         'use strict';
  13
  14         var mw,
  15                 hasOwn = Object.prototype.hasOwnProperty,
  16                 slice = Array.prototype.slice,
  17                 trackCallbacks = $.Callbacks( 'memory' ),
  18                 trackHandlers = [],
  19                 trackQueue = [];
  20
  21         /**
  22          * FNV132 hash function
  23          *
  24          * This function implements the 32-bit version of FNV-1.
  25          * It is equivalent to hash( 'fnv132', ... ) in PHP, except
  26          * its output is base 36 rather than hex.
  27          * See <https://en.wikipedia.org/wiki/FNV_hash_function>
  28          *
  29          * @private
  30          * @param {string} str String to hash
  31          * @return {string} hash as an seven-character base 36 string
  32          */
  33         function fnv132( str ) {
  34                 /*jshint bitwise:false */
  35                 var hash = 0x811C9DC5,
  36                         i;
  37
  38                 for ( i = 0; i < str.length; i++ ) {
  39                         hash += ( hash << 1 ) + ( hash << 4 ) + ( hash << 7 ) + ( hash << 8 ) + ( hash << 24 );
  40                         hash ^= str.charCodeAt( i );
  41                 }
  42
  43                 hash = ( hash >>> 0 ).toString( 36 );
  44                 while ( hash.length < 7 ) {
  45                         hash = '0' + hash;
  46                 }
  47
  48                 return hash;
  49         }
  50
  51         /**
  52          * Create an object that can be read from or written to from methods that allow
  53          * interaction both with single and multiple properties at once.
  54          *
  55          *     @example
  56          *
  57          *     var collection, query, results;
  58          *
  59          *     // Create your address book
  60          *     collection = new mw.Map();
  61          *
  62          *     // This data could be coming from an external source (eg. API/AJAX)
  63          *     collection.set( {
  64          *         'John Doe': 'john@example.org',
  65          *         'Jane Doe': 'jane@example.org',
  66          *         'George van Halen': 'gvanhalen@example.org'
  67          *     } );
  68          *
  69          *     wanted = ['John Doe', 'Jane Doe', 'Daniel Jackson'];
  70          *
  71          *     // You can detect missing keys first
  72          *     if ( !collection.exists( wanted ) ) {
  73          *         // One or more are missing (in this case: "Daniel Jackson")
  74          *         mw.log( 'One or more names were not found in your address book' );
  75          *     }
  76          *
  77          *     // Or just let it give you what it can. Optionally fill in from a default.
  78          *     results = collection.get( wanted, 'nobody@example.com' );
  79          *     mw.log( results['Jane Doe'] ); // "jane@example.org"
  80          *     mw.log( results['Daniel Jackson'] ); // "nobody@example.com"
  81          *
  82          * @class mw.Map
  83          *
  84          * @constructor
  85          * @param {Object|boolean} [values] The value-baring object to be mapped. Defaults to an
  86          *  empty object.
  87          *  For backwards-compatibility with mw.config, this can also be `true` in which case values
  88          *  are copied to the Window object as global variables (T72470). Values are copied in
  89          *  one direction only. Changes to globals are not reflected in the map.
  90          */
  91         function Map( values ) {
  92                 if ( values === true ) {
  93                         this.values = {};
  94
  95                         // Override #set to also set the global variable
  96                         this.set = function ( selection, value ) {
  97                                 var s;
  98
  99                                 if ( $.isPlainObject( selection ) ) {
 100                                         for ( s in selection ) {
 101                                                 setGlobalMapValue( this, s, selection[ s ] );
 102                                         }
 103                                         return true;
 104                                 }
 105                                 if ( typeof selection === 'string' && arguments.length ) {
 106                                         setGlobalMapValue( this, selection, value );
 107                                         return true;
 108                                 }
 109                                 return false;
 110                         };
 111
 112                         return;
 113                 }
 114
 115                 this.values = values || {};
 116         }
 117
 118         /**
 119          * Alias property to the global object.
 120          *
 121          * @private
 122          * @static
 123          * @param {mw.Map} map
 124          * @param {string} key
 125          * @param {Mixed} value
 126          */
 127         function setGlobalMapValue( map, key, value ) {
 128                 map.values[ key ] = value;
 129                 mw.log.deprecate(
 130                                 window,
 131                                 key,
 132                                 value,
 133                                 // Deprecation notice for mw.config globals (T58550, T72470)
 134                                 map === mw.config && 'Use mw.config instead.'
 135                 );
 136         }
 137
 138         Map.prototype = {
 139                 /**
 140                  * Get the value of one or more keys.
 141                  *
 142                  * If called with no arguments, all values are returned.
 143                  *
 144                  * @param {string|Array} [selection] Key or array of keys to retrieve values for.
 145                  * @param {Mixed} [fallback=null] Value for keys that don't exist.
 146                  * @return {Mixed|Object| null} If selection was a string, returns the value,
 147                  *  If selection was an array, returns an object of key/values.
 148                  *  If no selection is passed, the 'values' container is returned. (Beware that,
 149                  *  as is the default in JavaScript, the object is returned by reference.)
 150                  */
 151                 get: function ( selection, fallback ) {
 152                         var results, i;
 153                         // If we only do this in the `return` block, it'll fail for the
 154                         // call to get() from the mutli-selection block.
 155                         fallback = arguments.length > 1 ? fallback : null;
 156
 157                         if ( $.isArray( selection ) ) {
 158                                 selection = slice.call( selection );
 159                                 results = {};
 160                                 for ( i = 0; i < selection.length; i++ ) {
 161                                         results[ selection[ i ] ] = this.get( selection[ i ], fallback );
 162                                 }
 163                                 return results;
 164                         }
 165
 166                         if ( typeof selection === 'string' ) {
 167                                 if ( !hasOwn.call( this.values, selection ) ) {
 168                                         return fallback;
 169                                 }
 170                                 return this.values[ selection ];
 171                         }
 172
 173                         if ( selection === undefined ) {
 174                                 return this.values;
 175                         }
 176
 177                         // Invalid selection key
 178                         return null;
 179                 },
 180
 181                 /**
 182                  * Set one or more key/value pairs.
 183                  *
 184                  * @param {string|Object} selection Key to set value for, or object mapping keys to values
 185                  * @param {Mixed} [value] Value to set (optional, only in use when key is a string)
 186                  * @return {boolean} True on success, false on failure
 187                  */
 188                 set: function ( selection, value ) {
 189                         var s;
 190
 191                         if ( $.isPlainObject( selection ) ) {
 192                                 for ( s in selection ) {
 193                                         this.values[ s ] = selection[ s ];
 194                                 }
 195                                 return true;
 196                         }
 197                         if ( typeof selection === 'string' && arguments.length > 1 ) {
 198                                 this.values[ selection ] = value;
 199                                 return true;
 200                         }
 201                         return false;
 202                 },
 203
 204                 /**
 205                  * Check if one or more keys exist.
 206                  *
 207                  * @param {Mixed} selection Key or array of keys to check
 208                  * @return {boolean} True if the key(s) exist
 209                  */
 210                 exists: function ( selection ) {
 211                         var s;
 212
 213                         if ( $.isArray( selection ) ) {
 214                                 for ( s = 0; s < selection.length; s++ ) {
 215                                         if ( typeof selection[ s ] !== 'string' || !hasOwn.call( this.values, selection[ s ] ) ) {
 216                                                 return false;
 217                                         }
 218                                 }
 219                                 return true;
 220                         }
 221                         return typeof selection === 'string' && hasOwn.call( this.values, selection );
 222                 }
 223         };
 224
 225         /**
 226          * Object constructor for messages.
 227          *
 228          * Similar to the Message class in MediaWiki PHP.
 229          *
 230          * Format defaults to 'text'.
 231          *
 232          *     @example
 233          *
 234          *     var obj, str;
 235          *     mw.messages.set( {
 236          *         'hello': 'Hello world',
 237          *         'hello-user': 'Hello, $1!',
 238          *         'welcome-user': 'Welcome back to $2, $1! Last visit by $1: $3'
 239          *     } );
 240          *
 241          *     obj = new mw.Message( mw.messages, 'hello' );
 242          *     mw.log( obj.text() );
 243          *     // Hello world
 244          *
 245          *     obj = new mw.Message( mw.messages, 'hello-user', [ 'John Doe' ] );
 246          *     mw.log( obj.text() );
 247          *     // Hello, John Doe!
 248          *
 249          *     obj = new mw.Message( mw.messages, 'welcome-user', [ 'John Doe', 'Wikipedia', '2 hours ago' ] );
 250          *     mw.log( obj.text() );
 251          *     // Welcome back to Wikipedia, John Doe! Last visit by John Doe: 2 hours ago
 252          *
 253          *     // Using mw.message shortcut
 254          *     obj = mw.message( 'hello-user', 'John Doe' );
 255          *     mw.log( obj.text() );
 256          *     // Hello, John Doe!
 257          *
 258          *     // Using mw.msg shortcut
 259          *     str = mw.msg( 'hello-user', 'John Doe' );
 260          *     mw.log( str );
 261          *     // Hello, John Doe!
 262          *
 263          *     // Different formats
 264          *     obj = new mw.Message( mw.messages, 'hello-user', [ 'John "Wiki" <3 Doe' ] );
 265          *
 266          *     obj.format = 'text';
 267          *     str = obj.toString();
 268          *     // Same as:
 269          *     str = obj.text();
 270          *
 271          *     mw.log( str );
 272          *     // Hello, John "Wiki" <3 Doe!
 273          *
 274          *     mw.log( obj.escaped() );
 275          *     // Hello, John &quot;Wiki&quot; &lt;3 Doe!
 276          *
 277          * @class mw.Message
 278          *
 279          * @constructor
 280          * @param {mw.Map} map Message store
 281          * @param {string} key
 282          * @param {Array} [parameters]
 283          */
 284         function Message( map, key, parameters ) {
 285                 this.format = 'text';
 286                 this.map = map;
 287                 this.key = key;
 288                 this.parameters = parameters === undefined ? [] : slice.call( parameters );
 289                 return this;
 290         }
 291
 292         Message.prototype = {
 293                 /**
 294                  * Get parsed contents of the message.
 295                  *
 296                  * The default parser does simple $N replacements and nothing else.
 297                  * This may be overridden to provide a more complex message parser.
 298                  * The primary override is in the mediawiki.jqueryMsg module.
 299                  *
 300                  * This function will not be called for nonexistent messages.
 301                  *
 302                  * @return {string} Parsed message
 303                  */
 304                 parser: function () {
 305                         return mw.format.apply( null, [ this.map.get( this.key ) ].concat( this.parameters ) );
 306                 },
 307
 308                 /**
 309                  * Add (does not replace) parameters for `$N` placeholder values.
 310                  *
 311                  * @param {Array} parameters
 312                  * @chainable
 313                  */
 314                 params: function ( parameters ) {
 315                         var i;
 316                         for ( i = 0; i < parameters.length; i++ ) {
 317                                 this.parameters.push( parameters[ i ] );
 318                         }
 319                         return this;
 320                 },
 321
 322                 /**
 323                  * Convert message object to its string form based on current format.
 324                  *
 325                  * @return {string} Message as a string in the current form, or `<key>` if key
 326                  *  does not exist.
 327                  */
 328                 toString: function () {
 329                         var text;
 330
 331                         if ( !this.exists() ) {
 332                                 // Use <key> as text if key does not exist
 333                                 if ( this.format === 'escaped' || this.format === 'parse' ) {
 334                                         // format 'escaped' and 'parse' need to have the brackets and key html escaped
 335                                         return mw.html.escape( '<' + this.key + '>' );
 336                                 }
 337                                 return '<' + this.key + '>';
 338                         }
 339
 340                         if ( this.format === 'plain' || this.format === 'text' || this.format === 'parse' ) {
 341                                 text = this.parser();
 342                         }
 343
 344                         if ( this.format === 'escaped' ) {
 345                                 text = this.parser();
 346                                 text = mw.html.escape( text );
 347                         }
 348
 349                         return text;
 350                 },
 351
 352                 /**
 353                  * Change format to 'parse' and convert message to string
 354                  *
 355                  * If jqueryMsg is loaded, this parses the message text from wikitext
 356                  * (where supported) to HTML
 357                  *
 358                  * Otherwise, it is equivalent to plain.
 359                  *
 360                  * @return {string} String form of parsed message
 361                  */
 362                 parse: function () {
 363                         this.format = 'parse';
 364                         return this.toString();
 365                 },
 366
 367                 /**
 368                  * Change format to 'plain' and convert message to string
 369                  *
 370                  * This substitutes parameters, but otherwise does not change the
 371                  * message text.
 372                  *
 373                  * @return {string} String form of plain message
 374                  */
 375                 plain: function () {
 376                         this.format = 'plain';
 377                         return this.toString();
 378                 },
 379
 380                 /**
 381                  * Change format to 'text' and convert message to string
 382                  *
 383                  * If jqueryMsg is loaded, {{-transformation is done where supported
 384                  * (such as {{plural:}}, {{gender:}}, {{int:}}).
 385                  *
 386                  * Otherwise, it is equivalent to plain
 387                  *
 388                  * @return {string} String form of text message
 389                  */
 390                 text: function () {
 391                         this.format = 'text';
 392                         return this.toString();
 393                 },
 394
 395                 /**
 396                  * Change the format to 'escaped' and convert message to string
 397                  *
 398                  * This is equivalent to using the 'text' format (see #text), then
 399                  * HTML-escaping the output.
 400                  *
 401                  * @return {string} String form of html escaped message
 402                  */
 403                 escaped: function () {
 404                         this.format = 'escaped';
 405                         return this.toString();
 406                 },
 407
 408                 /**
 409                  * Check if a message exists
 410                  *
 411                  * @see mw.Map#exists
 412                  * @return {boolean}
 413                  */
 414                 exists: function () {
 415                         return this.map.exists( this.key );
 416                 }
 417         };
 418
 419         /**
 420          * @class mw
 421          */
 422         mw = {
 423
 424                 /**
 425                  * Get the current time, measured in milliseconds since January 1, 1970 (UTC).
 426                  *
 427                  * On browsers that implement the Navigation Timing API, this function will produce floating-point
 428                  * values with microsecond precision that are guaranteed to be monotonic. On all other browsers,
 429                  * it will fall back to using `Date`.
 430                  *
 431                  * @return {number} Current time
 432                  */
 433                 now: ( function () {
 434                         var perf = window.performance,
 435                                 navStart = perf && perf.timing && perf.timing.navigationStart;
 436                         return navStart && typeof perf.now === 'function' ?
 437                                 function () { return navStart + perf.now(); } :
 438                                 function () { return +new Date(); };
 439                 }() ),
 440
 441                 /**
 442                  * Format a string. Replace $1, $2 ... $N with positional arguments.
 443                  *
 444                  * Used by Message#parser().
 445                  *
 446                  * @since 1.25
 447                  * @param {string} formatString Format string
 448                  * @param {...Mixed} parameters Values for $N replacements
 449                  * @return {string} Formatted string
 450                  */
 451                 format: function ( formatString ) {
 452                         var parameters = slice.call( arguments, 1 );
 453                         return formatString.replace( /\$(\d+)/g, function ( str, match ) {
 454                                 var index = parseInt( match, 10 ) - 1;
 455                                 return parameters[ index ] !== undefined ? parameters[ index ] : '$' + match;
 456                         } );
 457                 },
 458
 459                 /**
 460                  * Track an analytic event.
 461                  *
 462                  * This method provides a generic means for MediaWiki JavaScript code to capture state
 463                  * information for analysis. Each logged event specifies a string topic name that describes
 464                  * the kind of event that it is. Topic names consist of dot-separated path components,
 465                  * arranged from most general to most specific. Each path component should have a clear and
 466                  * well-defined purpose.
 467                  *
 468                  * Data handlers are registered via `mw.trackSubscribe`, and receive the full set of
 469                  * events that match their subcription, including those that fired before the handler was
 470                  * bound.
 471                  *
 472                  * @param {string} topic Topic name
 473                  * @param {Object} [data] Data describing the event, encoded as an object
 474                  */
 475                 track: function ( topic, data ) {
 476                         trackQueue.push( { topic: topic, timeStamp: mw.now(), data: data } );
 477                         trackCallbacks.fire( trackQueue );
 478                 },
 479
 480                 /**
 481                  * Register a handler for subset of analytic events, specified by topic.
 482                  *
 483                  * Handlers will be called once for each tracked event, including any events that fired before the
 484                  * handler was registered; 'this' is set to a plain object with a 'timeStamp' property indicating
 485                  * the exact time at which the event fired, a string 'topic' property naming the event, and a
 486                  * 'data' property which is an object of event-specific data. The event topic and event data are
 487                  * also passed to the callback as the first and second arguments, respectively.
 488                  *
 489                  * @param {string} topic Handle events whose name starts with this string prefix
 490                  * @param {Function} callback Handler to call for each matching tracked event
 491                  * @param {string} callback.topic
 492                  * @param {Object} [callback.data]
 493                  */
 494                 trackSubscribe: function ( topic, callback ) {
 495                         var seen = 0;
 496                         function handler( trackQueue ) {
 497                                 var event;
 498                                 for ( ; seen < trackQueue.length; seen++ ) {
 499                                         event = trackQueue[ seen ];
 500                                         if ( event.topic.indexOf( topic ) === 0 ) {
 501                                                 callback.call( event, event.topic, event.data );
 502                                         }
 503                                 }
 504                         }
 505
 506                         trackHandlers.push( [ handler, callback ] );
 507
 508                         trackCallbacks.add( handler );
 509                 },
 510
 511                 /**
 512                  * Stop handling events for a particular handler
 513                  *
 514                  * @param {Function} callback
 515                  */
 516                 trackUnsubscribe: function ( callback ) {
 517                         trackHandlers = $.grep( trackHandlers, function ( fns ) {
 518                                 if ( fns[ 1 ] === callback ) {
 519                                         trackCallbacks.remove( fns[ 0 ] );
 520                                         // Ensure the tuple is removed to avoid holding on to closures
 521                                         return false;
 522                                 }
 523                                 return true;
 524                         } );
 525                 },
 526
 527                 // Expose Map constructor
 528                 Map: Map,
 529
 530                 // Expose Message constructor
 531                 Message: Message,
 532
 533                 /**
 534                  * Map of configuration values.
 535                  *
 536                  * Check out [the complete list of configuration values](https://www.mediawiki.org/wiki/Manual:Interface/JavaScript#mw.config)
 537                  * on mediawiki.org.
 538                  *
 539                  * If `$wgLegacyJavaScriptGlobals` is true, this Map will add its values to the
 540                  * global `window` object.
 541                  *
 542                  * @property {mw.Map} config
 543                  */
 544                 // Dummy placeholder later assigned in ResourceLoaderStartUpModule
 545                 config: null,
 546
 547                 /**
 548                  * Empty object for third-party libraries, for cases where you don't
 549                  * want to add a new global, or the global is bad and needs containment
 550                  * or wrapping.
 551                  *
 552                  * @property
 553                  */
 554                 libs: {},
 555
 556                 /**
 557                  * Access container for deprecated functionality that can be moved from
 558                  * from their legacy location and attached to this object (e.g. a global
 559                  * function that is deprecated and as stop-gap can be exposed through here).
 560                  *
 561                  * This was reserved for future use but never ended up being used.
 562                  *
 563                  * @deprecated since 1.22 Let deprecated identifiers keep their original name
 564                  *  and use mw.log#deprecate to create an access container for tracking.
 565                  * @property
 566                  */
 567                 legacy: {},
 568
 569                 /**
 570                  * Store for messages.
 571                  *
 572                  * @property {mw.Map}
 573                  */
 574                 messages: new Map(),
 575
 576                 /**
 577                  * Store for templates associated with a module.
 578                  *
 579                  * @property {mw.Map}
 580                  */
 581                 templates: new Map(),
 582
 583                 /**
 584                  * Get a message object.
 585                  *
 586                  * Shortcut for `new mw.Message( mw.messages, key, parameters )`.
 587                  *
 588                  * @see mw.Message
 589                  * @param {string} key Key of message to get
 590                  * @param {...Mixed} parameters Values for $N replacements
 591                  * @return {mw.Message}
 592                  */
 593                 message: function ( key ) {
 594                         var parameters = slice.call( arguments, 1 );
 595                         return new Message( mw.messages, key, parameters );
 596                 },
 597
 598                 /**
 599                  * Get a message string using the (default) 'text' format.
 600                  *
 601                  * Shortcut for `mw.message( key, parameters... ).text()`.
 602                  *
 603                  * @see mw.Message
 604                  * @param {string} key Key of message to get
 605                  * @param {...Mixed} parameters Values for $N replacements
 606                  * @return {string}
 607                  */
 608                 msg: function () {
 609                         return mw.message.apply( mw.message, arguments ).toString();
 610                 },
 611
 612                 /**
 613                  * Dummy placeholder for {@link mw.log}
 614                  *
 615                  * @method
 616                  */
 617                 log: ( function () {
 618                         // Also update the restoration of methods in mediawiki.log.js
 619                         // when adding or removing methods here.
 620                         var log = function () {},
 621                                 console = window.console;
 622
 623                         /**
 624                          * @class mw.log
 625                          * @singleton
 626                          */
 627
 628                         /**
 629                          * Write a message to the console's warning channel.
 630                          * Actions not supported by the browser console are silently ignored.
 631                          *
 632                          * @param {...string} msg Messages to output to console
 633                          */
 634                         log.warn = console && console.warn && Function.prototype.bind ?
 635                                 Function.prototype.bind.call( console.warn, console ) :
 636                                 $.noop;
 637
 638                         /**
 639                          * Write a message to the console's error channel.
 640                          *
 641                          * Most browsers provide a stacktrace by default if the argument
 642                          * is a caught Error object.
 643                          *
 644                          * @since 1.26
 645                          * @param {Error|...string} msg Messages to output to console
 646                          */
 647                         log.error = console && console.error && Function.prototype.bind ?
 648                                 Function.prototype.bind.call( console.error, console ) :
 649                                 $.noop;
 650
 651                         /**
 652                          * Create a property in a host object that, when accessed, will produce
 653                          * a deprecation warning in the console with backtrace.
 654                          *
 655                          * @param {Object} obj Host object of deprecated property
 656                          * @param {string} key Name of property to create in `obj`
 657                          * @param {Mixed} val The value this property should return when accessed
 658                          * @param {string} [msg] Optional text to include in the deprecation message
 659                          */
 660                         log.deprecate = !Object.defineProperty ? function ( obj, key, val ) {
 661                                 obj[ key ] = val;
 662                         } : function ( obj, key, val, msg ) {
 663                                 msg = 'Use of "' + key + '" is deprecated.' + ( msg ? ( ' ' + msg ) : '' );
 664                                 Object.defineProperty( obj, key, {
 665                                         configurable: true,
 666                                         enumerable: true,
 667                                         get: function () {
 668                                                 mw.track( 'mw.deprecate', key );
 669                                                 mw.log.warn( msg );
 670                                                 return val;
 671                                         },
 672                                         set: function ( newVal ) {
 673                                                 mw.track( 'mw.deprecate', key );
 674                                                 mw.log.warn( msg );
 675                                                 val = newVal;
 676                                         }
 677                                 } );
 678
 679                         };
 680
 681                         return log;
 682                 }() ),
 683
 684                 /**
 685                  * Client for ResourceLoader server end point.
 686                  *
 687                  * This client is in charge of maintaining the module registry and state
 688                  * machine, initiating network (batch) requests for loading modules, as
 689                  * well as dependency resolution and execution of source code.
 690                  *
 691                  * For more information, refer to
 692                  * <https://www.mediawiki.org/wiki/ResourceLoader/Features>
 693                  *
 694                  * @class mw.loader
 695                  * @singleton
 696                  */
 697                 loader: ( function () {
 698
 699                         /**
 700                          * Fired via mw.track on various resource loading errors.
 701                          *
 702                          * @event resourceloader_exception
 703                          * @param {Error|Mixed} e The error that was thrown. Almost always an Error
 704                          *   object, but in theory module code could manually throw something else, and that
 705                          *   might also end up here.
 706                          * @param {string} [module] Name of the module which caused the error. Omitted if the
 707                          *   error is not module-related or the module cannot be easily identified due to
 708                          *   batched handling.
 709                          * @param {string} source Source of the error. Possible values:
 710                          *
 711                          *   - style: stylesheet error (only affects old IE where a special style loading method
 712                          *     is used)
 713                          *   - load-callback: exception thrown by user callback
 714                          *   - module-execute: exception thrown by module code
 715                          *   - store-eval: could not evaluate module code cached in localStorage
 716                          *   - store-localstorage-init: localStorage or JSON parse error in mw.loader.store.init
 717                          *   - store-localstorage-json: JSON conversion error in mw.loader.store.set
 718                          *   - store-localstorage-update: localStorage or JSON conversion error in mw.loader.store.update
 719                          */
 720
 721                         /**
 722                          * Fired via mw.track on resource loading error conditions.
 723                          *
 724                          * @event resourceloader_assert
 725                          * @param {string} source Source of the error. Possible values:
 726                          *
 727                          *   - bug-T59567: failed to cache script due to an Opera function -> string conversion
 728                          *     bug; see <https://phabricator.wikimedia.org/T59567> for details
 729                          */
 730
 731                         /**
 732                          * Mapping of registered modules.
 733                          *
 734                          * See #implement and #execute for exact details on support for script, style and messages.
 735                          *
 736                          * Format:
 737                          *
 738                          *     {
 739                          *         'moduleName': {
 740                          *             // From mw.loader.register()
 741                          *             'version': '########' (hash)
 742                          *             'dependencies': ['required.foo', 'bar.also', ...], (or) function () {}
 743                          *             'group': 'somegroup', (or) null
 744                          *             'source': 'local', (or) 'anotherwiki'
 745                          *             'skip': 'return !!window.Example', (or) null
 746                          *             'module': export Object
 747                          *
 748                          *             // Set from execute() or mw.loader.state()
 749                          *             'state': 'registered', 'loaded', 'loading', 'ready', 'error', or 'missing'
 750                          *
 751                          *             // Optionally added at run-time by mw.loader.implement()
 752                          *             'skipped': true
 753                          *             'script': closure, array of urls, or string
 754                          *             'style': { ... } (see #execute)
 755                          *             'messages': { 'key': 'value', ... }
 756                          *         }
 757                          *     }
 758                          *
 759                          * State machine:
 760                          *
 761                          * - `registered`:
 762                          *    The module is known to the system but not yet requested.
 763                          *    Meta data is registered via mw.loader#register. Calls to that method are
 764                          *    generated server-side by the startup module.
 765                          * - `loading`:
 766                          *    The module is requested through mw.loader (either directly or as dependency of
 767                          *    another module). The client will be fetching module contents from the server.
 768                          *    The contents are then stashed in the registry via mw.loader#implement.
 769                          * - `loaded`:
 770                          *    The module has been requested from the server and stashed via mw.loader#implement.
 771                          *    If the module has no more dependencies in-fight, the module will be executed
 772                          *    right away. Otherwise execution is deferred, controlled via #handlePending.
 773                          * - `executing`:
 774                          *    The module is being executed.
 775                          * - `ready`:
 776                          *    The module has been successfully executed.
 777                          * - `error`:
 778                          *    The module (or one of its dependencies) produced an error during execution.
 779                          * - `missing`:
 780                          *    The module was registered client-side and requested, but the server denied knowledge
 781                          *    of the module's existence.
 782                          *
 783                          * @property
 784                          * @private
 785                          */
 786                         var registry = {},
 787                                 // Mapping of sources, keyed by source-id, values are strings.
 788                                 //
 789                                 // Format:
 790                                 //
 791                                 //     {
 792                                 //         'sourceId': 'http://example.org/w/load.php'
 793                                 //     }
 794                                 //
 795                                 sources = {},
 796
 797                                 // List of modules which will be loaded as when ready
 798                                 batch = [],
 799
 800                                 // Pending queueModuleScript() requests
 801                                 handlingPendingRequests = false,
 802                                 pendingRequests = [],
 803
 804                                 // List of modules to be loaded
 805                                 queue = [],
 806
 807                                 /**
 808                                  * List of callback jobs waiting for modules to be ready.
 809                                  *
 810                                  * Jobs are created by #request() and run by #handlePending().
 811                                  *
 812                                  * Typically when a job is created for a module, the job's dependencies contain
 813                                  * both the module being requested and all its recursive dependencies.
 814                                  *
 815                                  * Format:
 816                                  *
 817                                  *     {
 818                                  *         'dependencies': [ module names ],
 819                                  *         'ready': Function callback
 820                                  *         'error': Function callback
 821                                  *     }
 822                                  *
 823                                  * @property {Object[]} jobs
 824                                  * @private
 825                                  */
 826                                 jobs = [],
 827
 828                                 // For getMarker()
 829                                 marker = null,
 830
 831                                 // For addEmbeddedCSS()
 832                                 cssBuffer = '',
 833                                 cssBufferTimer = null,
 834                                 cssCallbacks = $.Callbacks(),
 835                                 isIE9 = document.documentMode === 9;
 836
 837                         function getMarker() {
 838                                 if ( !marker ) {
 839                                         // Cache
 840                                         marker = document.querySelector( 'meta[name="ResourceLoaderDynamicStyles"]' );
 841                                         if ( !marker ) {
 842                                                 mw.log( 'Create <meta name="ResourceLoaderDynamicStyles"> dynamically' );
 843                                                 marker = $( '<meta>' ).attr( 'name', 'ResourceLoaderDynamicStyles' ).appendTo( 'head' )[ 0 ];
 844                                         }
 845                                 }
 846                                 return marker;
 847                         }
 848
 849                         /**
 850                          * Create a new style element and add it to the DOM.
 851                          *
 852                          * @private
 853                          * @param {string} text CSS text
 854                          * @param {Node} [nextNode] The element where the style tag
 855                          *  should be inserted before
 856                          * @return {HTMLElement} Reference to the created style element
 857                          */
 858                         function newStyleTag( text, nextNode ) {
 859                                 var s = document.createElement( 'style' );
 860
 861                                 s.appendChild( document.createTextNode( text ) );
 862                                 if ( nextNode && nextNode.parentNode ) {
 863                                         nextNode.parentNode.insertBefore( s, nextNode );
 864                                 } else {
 865                                         document.getElementsByTagName( 'head' )[ 0 ].appendChild( s );
 866                                 }
 867
 868                                 return s;
 869                         }
 870
 871                         /**
 872                          * Add a bit of CSS text to the current browser page.
 873                          *
 874                          * The CSS will be appended to an existing ResourceLoader-created `<style>` tag
 875                          * or create a new one based on whether the given `cssText` is safe for extension.
 876                          *
 877                          * @param {string} [cssText=cssBuffer] If called without cssText,
 878                          *  the internal buffer will be inserted instead.
 879                          * @param {Function} [callback]
 880                          */
 881                         function addEmbeddedCSS( cssText, callback ) {
 882                                 var $style, styleEl;
 883
 884                                 function fireCallbacks() {
 885                                         var oldCallbacks = cssCallbacks;
 886                                         // Reset cssCallbacks variable so it's not polluted by any calls to
 887                                         // addEmbeddedCSS() from one of the callbacks (T105973)
 888                                         cssCallbacks = $.Callbacks();
 889                                         oldCallbacks.fire().empty();
 890                                 }
 891
 892                                 if ( callback ) {
 893                                         cssCallbacks.add( callback );
 894                                 }
 895
 896                                 // Yield once before creating the <style> tag. This lets multiple stylesheets
 897                                 // accumulate into one buffer, allowing us to reduce how often new stylesheets
 898                                 // are inserted in the browser. Appending a stylesheet and waiting for the
 899                                 // browser to repaint is fairly expensive. (T47810)
 900                                 if ( cssText ) {
 901                                         // Don't extend the buffer if the item needs its own stylesheet.
 902                                         // Keywords like `@import` are only valid at the start of a stylesheet (T37562).
 903                                         if ( !cssBuffer || cssText.slice( 0, '@import'.length ) !== '@import' ) {
 904                                                 // Linebreak for somewhat distinguishable sections
 905                                                 cssBuffer += '\n' + cssText;
 906                                                 // TODO: Using requestAnimationFrame would perform better by not injecting
 907                                                 // styles while the browser is busy painting.
 908                                                 if ( !cssBufferTimer ) {
 909                                                         cssBufferTimer = setTimeout( function () {
 910                                                                 // Support: Firefox < 13
 911                                                                 // Firefox 12 has non-standard behaviour of passing a number
 912                                                                 // as first argument to a setTimeout callback.
 913                                                                 // http://benalman.com/news/2009/07/the-mysterious-firefox-settime/
 914                                                                 addEmbeddedCSS();
 915                                                         } );
 916                                                 }
 917                                                 return;
 918                                         }
 919
 920                                 // This is a scheduled flush for the buffer
 921                                 } else {
 922                                         cssBufferTimer = null;
 923                                         cssText = cssBuffer;
 924                                         cssBuffer = '';
 925                                 }
 926
 927                                 // By default, always create a new <style>. Appending text to a <style> tag is
 928                                 // is a performance anti-pattern as it requires CSS to be reparsed (T47810).
 929                                 //
 930                                 // Support: IE 6-9
 931                                 // Try to re-use existing <style> tags due to the IE stylesheet limit (T33676).
 932                                 if ( isIE9 ) {
 933                                         $style = $( getMarker() ).prev();
 934                                         // Verify that the element before the marker actually is a <style> tag created
 935                                         // by mw.loader (not some other style tag, or e.g. a <meta> tag).
 936                                         if ( $style.data( 'ResourceLoaderDynamicStyleTag' ) ) {
 937                                                 styleEl = $style[ 0 ];
 938                                                 styleEl.appendChild( document.createTextNode( cssText ) );
 939                                                 fireCallbacks();
 940                                                 return;
 941                                         }
 942                                         // Else: No existing tag to reuse. Continue below and create the first one.
 943                                 }
 944
 945                                 $style = $( newStyleTag( cssText, getMarker() ) );
 946
 947                                 if ( isIE9 ) {
 948                                         $style.data( 'ResourceLoaderDynamicStyleTag', true );
 949                                 }
 950
 951                                 fireCallbacks();
 952                         }
 953
 954                         /**
 955                          * @since 1.26
 956                          * @param {Array} modules List of module names
 957                          * @return {string} Hash of concatenated version hashes.
 958                          */
 959                         function getCombinedVersion( modules ) {
 960                                 var hashes = $.map( modules, function ( module ) {
 961                                         return registry[ module ].version;
 962                                 } );
 963                                 return fnv132( hashes.join( '' ) );
 964                         }
 965
 966                         /**
 967                          * Determine whether all dependencies are in state 'ready', which means we may
 968                          * execute the module or job now.
 969                          *
 970                          * @private
 971                          * @param {Array} modules Names of modules to be checked
 972                          * @return {boolean} True if all modules are in state 'ready', false otherwise
 973                          */
 974                         function allReady( modules ) {
 975                                 var i;
 976                                 for ( i = 0; i < modules.length; i++ ) {
 977                                         if ( mw.loader.getState( modules[ i ] ) !== 'ready' ) {
 978                                                 return false;
 979                                         }
 980                                 }
 981                                 return true;
 982                         }
 983
 984                         /**
 985                          * Determine whether all dependencies are in state 'ready', which means we may
 986                          * execute the module or job now.
 987                          *
 988                          * @private
 989                          * @param {Array} modules Names of modules to be checked
 990                          * @return {boolean} True if no modules are in state 'error' or 'missing', false otherwise
 991                          */
 992                         function anyFailed( modules ) {
 993                                 var i, state;
 994                                 for ( i = 0; i < modules.length; i++ ) {
 995                                         state = mw.loader.getState( modules[ i ] );
 996                                         if ( state === 'error' || state === 'missing' ) {
 997                                                 return true;
 998                                         }
 999                                 }
1000                                 return false;
1001                         }
1002
1003                         /**
1004                          * A module has entered state 'ready', 'error', or 'missing'. Automatically update
1005                          * pending jobs and modules that depend upon this module. If the given module failed,
1006                          * propagate the 'error' state up the dependency tree. Otherwise, go ahead and execute
1007                          * all jobs/modules now having their dependencies satisfied.
1008                          *
1009                          * Jobs that depend on a failed module, will have their error callback ran (if any).
1010                          *
1011                          * @private
1012                          * @param {string} module Name of module that entered one of the states 'ready', 'error', or 'missing'.
1013                          */
1014                         function handlePending( module ) {
1015                                 var j, job, hasErrors, m, stateChange;
1016
1017                                 if ( registry[ module ].state === 'error' || registry[ module ].state === 'missing' ) {
1018                                         // If the current module failed, mark all dependent modules also as failed.
1019                                         // Iterate until steady-state to propagate the error state upwards in the
1020                                         // dependency tree.
1021                                         do {
1022                                                 stateChange = false;
1023                                                 for ( m in registry ) {
1024                                                         if ( registry[ m ].state !== 'error' && registry[ m ].state !== 'missing' ) {
1025                                                                 if ( anyFailed( registry[ m ].dependencies ) ) {
1026                                                                         registry[ m ].state = 'error';
1027                                                                         stateChange = true;
1028                                                                 }
1029                                                         }
1030                                                 }
1031                                         } while ( stateChange );
1032                                 }
1033
1034                                 // Execute all jobs whose dependencies are either all satisfied or contain at least one failed module.
1035                                 for ( j = 0; j < jobs.length; j++ ) {
1036                                         hasErrors = anyFailed( jobs[ j ].dependencies );
1037                                         if ( hasErrors || allReady( jobs[ j ].dependencies ) ) {
1038                                                 // All dependencies satisfied, or some have errors
1039                                                 job = jobs[ j ];
1040                                                 jobs.splice( j, 1 );
1041                                                 j -= 1;
1042                                                 try {
1043                                                         if ( hasErrors ) {
1044                                                                 if ( $.isFunction( job.error ) ) {
1045                                                                         job.error( new Error( 'Module ' + module + ' has failed dependencies' ), [ module ] );
1046                                                                 }
1047                                                         } else {
1048                                                                 if ( $.isFunction( job.ready ) ) {
1049                                                                         job.ready();
1050                                                                 }
1051                                                         }
1052                                                 } catch ( e ) {
1053                                                         // A user-defined callback raised an exception.
1054                                                         // Swallow it to protect our state machine!
1055                                                         mw.track( 'resourceloader.exception', { exception: e, module: module, source: 'load-callback' } );
1056                                                 }
1057                                         }
1058                                 }
1059
1060                                 if ( registry[ module ].state === 'ready' ) {
1061                                         // The current module became 'ready'. Set it in the module store, and recursively execute all
1062                                         // dependent modules that are loaded and now have all dependencies satisfied.
1063                                         mw.loader.store.set( module, registry[ module ] );
1064                                         for ( m in registry ) {
1065                                                 if ( registry[ m ].state === 'loaded' && allReady( registry[ m ].dependencies ) ) {
1066                                                         execute( m );
1067                                                 }
1068                                         }
1069                                 }
1070                         }
1071
1072                         /**
1073                          * Resolve dependencies and detect circular references.
1074                          *
1075                          * @private
1076                          * @param {string} module Name of the top-level module whose dependencies shall be
1077                          *  resolved and sorted.
1078                          * @param {Array} resolved Returns a topological sort of the given module and its
1079                          *  dependencies, such that later modules depend on earlier modules. The array
1080                          *  contains the module names. If the array contains already some module names,
1081                          *  this function appends its result to the pre-existing array.
1082                          * @param {Object} [unresolved] Hash used to track the current dependency
1083                          *  chain; used to report loops in the dependency graph.
1084                          * @throws {Error} If any unregistered module or a dependency loop is encountered
1085                          */
1086                         function sortDependencies( module, resolved, unresolved ) {
1087                                 var i, deps, skip;
1088
1089                                 if ( !hasOwn.call( registry, module ) ) {
1090                                         throw new Error( 'Unknown dependency: ' + module );
1091                                 }
1092
1093                                 if ( registry[ module ].skip !== null ) {
1094                                         /*jshint evil:true */
1095                                         skip = new Function( registry[ module ].skip );
1096                                         registry[ module ].skip = null;
1097                                         if ( skip() ) {
1098                                                 registry[ module ].skipped = true;
1099                                                 registry[ module ].dependencies = [];
1100                                                 registry[ module ].state = 'ready';
1101                                                 handlePending( module );
1102                                                 return;
1103                                         }
1104                                 }
1105
1106                                 // Resolves dynamic loader function and replaces it with its own results
1107                                 if ( $.isFunction( registry[ module ].dependencies ) ) {
1108                                         registry[ module ].dependencies = registry[ module ].dependencies();
1109                                         // Ensures the module's dependencies are always in an array
1110                                         if ( typeof registry[ module ].dependencies !== 'object' ) {
1111                                                 registry[ module ].dependencies = [ registry[ module ].dependencies ];
1112                                         }
1113                                 }
1114                                 if ( $.inArray( module, resolved ) !== -1 ) {
1115                                         // Module already resolved; nothing to do
1116                                         return;
1117                                 }
1118                                 // Create unresolved if not passed in
1119                                 if ( !unresolved ) {
1120                                         unresolved = {};
1121                                 }
1122                                 // Tracks down dependencies
1123                                 deps = registry[ module ].dependencies;
1124                                 for ( i = 0; i < deps.length; i++ ) {
1125                                         if ( $.inArray( deps[ i ], resolved ) === -1 ) {
1126                                                 if ( unresolved[ deps[ i ] ] ) {
1127                                                         throw new Error( mw.format(
1128                                                                 'Circular reference detected: $1 -> $2',
1129                                                                 module,
1130                                                                 deps[ i ]
1131                                                         ) );
1132                                                 }
1133
1134                                                 // Add to unresolved
1135                                                 unresolved[ module ] = true;
1136                                                 sortDependencies( deps[ i ], resolved, unresolved );
1137                                         }
1138                                 }
1139                                 resolved.push( module );
1140                         }
1141
1142                         /**
1143                          * Get names of module that a module depends on, in their proper dependency order.
1144                          *
1145                          * @private
1146                          * @param {string[]} modules Array of string module names
1147                          * @return {Array} List of dependencies, including 'module'.
1148                          */
1149                         function resolve( modules ) {
1150                                 var resolved = [];
1151                                 $.each( modules, function ( idx, module ) {
1152                                         sortDependencies( module, resolved );
1153                                 } );
1154                                 return resolved;
1155                         }
1156
1157                         /**
1158                          * Load and execute a script.
1159                          *
1160                          * @private
1161                          * @param {string} src URL to script, will be used as the src attribute in the script tag
1162                          * @return {jQuery.Promise}
1163                          */
1164                         function addScript( src ) {
1165                                 return $.ajax( {
1166                                         url: src,
1167                                         dataType: 'script',
1168                                         // Force jQuery behaviour to be for crossDomain. Otherwise jQuery would use
1169                                         // XHR for a same domain request instead of <script>, which changes the request
1170                                         // headers (potentially missing a cache hit), and reduces caching in general
1171                                         // since browsers cache XHR much less (if at all). And XHR means we retreive
1172                                         // text, so we'd need to $.globalEval, which then messes up line numbers.
1173                                         crossDomain: true,
1174                                         cache: true
1175                                 } );
1176                         }
1177
1178                         /**
1179                          * Queue the loading and execution of a script for a particular module.
1180                          *
1181                          * @private
1182                          * @param {string} src URL of the script
1183                          * @param {string} [moduleName] Name of currently executing module
1184                          * @return {jQuery.Promise}
1185                          */
1186                         function queueModuleScript( src, moduleName ) {
1187                                 var r = $.Deferred();
1188
1189                                 pendingRequests.push( function () {
1190                                         if ( moduleName && hasOwn.call( registry, moduleName ) ) {
1191                                                 window.require = mw.loader.require;
1192                                                 window.module = registry[ moduleName ].module;
1193                                         }
1194                                         addScript( src ).always( function () {
1195                                                 // Clear environment
1196                                                 delete window.require;
1197                                                 delete window.module;
1198                                                 r.resolve();
1199
1200                                                 // Start the next one (if any)
1201                                                 if ( pendingRequests[ 0 ] ) {
1202                                                         pendingRequests.shift()();
1203                                                 } else {
1204                                                         handlingPendingRequests = false;
1205                                                 }
1206                                         } );
1207                                 } );
1208                                 if ( !handlingPendingRequests && pendingRequests[ 0 ] ) {
1209                                         handlingPendingRequests = true;
1210                                         pendingRequests.shift()();
1211                                 }
1212                                 return r.promise();
1213                         }
1214
1215                         /**
1216                          * Utility function for execute()
1217                          *
1218                          * @ignore
1219                          */
1220                         function addLink( media, url ) {
1221                                 var el = document.createElement( 'link' );
1222
1223                                 el.rel = 'stylesheet';
1224                                 if ( media && media !== 'all' ) {
1225                                         el.media = media;
1226                                 }
1227                                 // If you end up here from an IE exception "SCRIPT: Invalid property value.",
1228                                 // see #addEmbeddedCSS, bug 31676, and bug 47277 for details.
1229                                 el.href = url;
1230
1231                                 $( getMarker() ).before( el );
1232                         }
1233
1234                         /**
1235                          * Executes a loaded module, making it ready to use
1236                          *
1237                          * @private
1238                          * @param {string} module Module name to execute
1239                          */
1240                         function execute( module ) {
1241                                 var key, value, media, i, urls, cssHandle, checkCssHandles, runScript,
1242                                         cssHandlesRegistered = false;
1243
1244                                 if ( !hasOwn.call( registry, module ) ) {
1245                                         throw new Error( 'Module has not been registered yet: ' + module );
1246                                 }
1247                                 if ( registry[ module ].state !== 'loaded' ) {
1248                                         throw new Error( 'Module in state "' + registry[ module ].state + '" may not be executed: ' + module );
1249                                 }
1250
1251                                 registry[ module ].state = 'executing';
1252
1253                                 runScript = function () {
1254                                         var script, markModuleReady, nestedAddScript, legacyWait,
1255                                                 // Expand to include dependencies since we have to exclude both legacy modules
1256                                                 // and their dependencies from the legacyWait (to prevent a circular dependency).
1257                                                 legacyModules = resolve( mw.config.get( 'wgResourceLoaderLegacyModules', [] ) );
1258                                         try {
1259                                                 script = registry[ module ].script;
1260                                                 markModuleReady = function () {
1261                                                         registry[ module ].state = 'ready';
1262                                                         handlePending( module );
1263                                                 };
1264                                                 nestedAddScript = function ( arr, callback, i ) {
1265                                                         // Recursively call queueModuleScript() in its own callback
1266                                                         // for each element of arr.
1267                                                         if ( i >= arr.length ) {
1268                                                                 // We're at the end of the array
1269                                                                 callback();
1270                                                                 return;
1271                                                         }
1272
1273                                                         queueModuleScript( arr[ i ], module ).always( function () {
1274                                                                 nestedAddScript( arr, callback, i + 1 );
1275                                                         } );
1276                                                 };
1277
1278                                                 legacyWait = ( $.inArray( module, legacyModules ) !== -1 )
1279                                                         ? $.Deferred().resolve()
1280                                                         : mw.loader.using( legacyModules );
1281
1282                                                 legacyWait.always( function () {
1283                                                         if ( $.isArray( script ) ) {
1284                                                                 nestedAddScript( script, markModuleReady, 0 );
1285                                                         } else if ( $.isFunction( script ) ) {
1286                                                                 // Pass jQuery twice so that the signature of the closure which wraps
1287                                                                 // the script can bind both '$' and 'jQuery'.
1288                                                                 script( $, $, mw.loader.require, registry[ module ].module );
1289                                                                 markModuleReady();
1290
1291                                                         } else if ( typeof script === 'string' ) {
1292                                                                 // Site and user modules are legacy scripts that run in the global scope.
1293                                                                 // This is transported as a string instead of a function to avoid needing
1294                                                                 // to use string manipulation to undo the function wrapper.
1295                                                                 if ( module === 'user' ) {
1296                                                                         // Implicit dependency on the site module. Not real dependency because
1297                                                                         // it should run after 'site' regardless of whether it succeeds or fails.
1298                                                                         mw.loader.using( 'site' ).always( function () {
1299                                                                                 $.globalEval( script );
1300                                                                                 markModuleReady();
1301                                                                         } );
1302                                                                 } else {
1303                                                                         $.globalEval( script );
1304                                                                         markModuleReady();
1305                                                                 }
1306                                                         } else {
1307                                                                 // Module without script
1308                                                                 markModuleReady();
1309                                                         }
1310                                                 } );
1311                                         } catch ( e ) {
1312                                                 // This needs to NOT use mw.log because these errors are common in production mode
1313                                                 // and not in debug mode, such as when a symbol that should be global isn't exported
1314                                                 registry[ module ].state = 'error';
1315                                                 mw.track( 'resourceloader.exception', { exception: e, module: module, source: 'module-execute' } );
1316                                                 handlePending( module );
1317                                         }
1318                                 };
1319
1320                                 // Add localizations to message system
1321                                 if ( registry[ module ].messages ) {
1322                                         mw.messages.set( registry[ module ].messages );
1323                                 }
1324
1325                                 // Initialise templates
1326                                 if ( registry[ module ].templates ) {
1327                                         mw.templates.set( module, registry[ module ].templates );
1328                                 }
1329
1330                                 // Make sure we don't run the scripts until all stylesheet insertions have completed.
1331                                 ( function () {
1332                                         var pending = 0;
1333                                         checkCssHandles = function () {
1334                                                 // cssHandlesRegistered ensures we don't take off too soon, e.g. when
1335                                                 // one of the cssHandles is fired while we're still creating more handles.
1336                                                 if ( cssHandlesRegistered && pending === 0 && runScript ) {
1337                                                         runScript();
1338                                                         runScript = undefined; // Revoke
1339                                                 }
1340                                         };
1341                                         cssHandle = function () {
1342                                                 var check = checkCssHandles;
1343                                                 pending++;
1344                                                 return function () {
1345                                                         if ( check ) {
1346                                                                 pending--;
1347                                                                 check();
1348                                                                 check = undefined; // Revoke
1349                                                         }
1350                                                 };
1351                                         };
1352                                 }() );
1353
1354                                 // Process styles (see also mw.loader.implement)
1355                                 // * back-compat: { <media>: css }
1356                                 // * back-compat: { <media>: [url, ..] }
1357                                 // * { "css": [css, ..] }
1358                                 // * { "url": { <media>: [url, ..] } }
1359                                 if ( registry[ module ].style ) {
1360                                         for ( key in registry[ module ].style ) {
1361                                                 value = registry[ module ].style[ key ];
1362                                                 media = undefined;
1363
1364                                                 if ( key !== 'url' && key !== 'css' ) {
1365                                                         // Backwards compatibility, key is a media-type
1366                                                         if ( typeof value === 'string' ) {
1367                                                                 // back-compat: { <media>: css }
1368                                                                 // Ignore 'media' because it isn't supported (nor was it used).
1369                                                                 // Strings are pre-wrapped in "@media". The media-type was just ""
1370                                                                 // (because it had to be set to something).
1371                                                                 // This is one of the reasons why this format is no longer used.
1372                                                                 addEmbeddedCSS( value, cssHandle() );
1373                                                         } else {
1374                                                                 // back-compat: { <media>: [url, ..] }
1375                                                                 media = key;
1376                                                                 key = 'bc-url';
1377                                                         }
1378                                                 }
1379
1380                                                 // Array of css strings in key 'css',
1381                                                 // or back-compat array of urls from media-type
1382                                                 if ( $.isArray( value ) ) {
1383                                                         for ( i = 0; i < value.length; i++ ) {
1384                                                                 if ( key === 'bc-url' ) {
1385                                                                         // back-compat: { <media>: [url, ..] }
1386                                                                         addLink( media, value[ i ] );
1387                                                                 } else if ( key === 'css' ) {
1388                                                                         // { "css": [css, ..] }
1389                                                                         addEmbeddedCSS( value[ i ], cssHandle() );
1390                                                                 }
1391                                                         }
1392                                                 // Not an array, but a regular object
1393                                                 // Array of urls inside media-type key
1394                                                 } else if ( typeof value === 'object' ) {
1395                                                         // { "url": { <media>: [url, ..] } }
1396                                                         for ( media in value ) {
1397                                                                 urls = value[ media ];
1398                                                                 for ( i = 0; i < urls.length; i++ ) {
1399                                                                         addLink( media, urls[ i ] );
1400                                                                 }
1401                                                         }
1402                                                 }
1403                                         }
1404                                 }
1405
1406                                 // Kick off.
1407                                 cssHandlesRegistered = true;
1408                                 checkCssHandles();
1409                         }
1410
1411                         /**
1412                          * Adds all dependencies to the queue with optional callbacks to be run
1413                          * when the dependencies are ready or fail
1414                          *
1415                          * @private
1416                          * @param {string|string[]} dependencies Module name or array of string module names
1417                          * @param {Function} [ready] Callback to execute when all dependencies are ready
1418                          * @param {Function} [error] Callback to execute when any dependency fails
1419                          */
1420                         function request( dependencies, ready, error ) {
1421                                 // Allow calling by single module name
1422                                 if ( typeof dependencies === 'string' ) {
1423                                         dependencies = [ dependencies ];
1424                                 }
1425
1426                                 // Add ready and error callbacks if they were given
1427                                 if ( ready !== undefined || error !== undefined ) {
1428                                         jobs.push( {
1429                                                 // Narrow down the list to modules that are worth waiting for
1430                                                 dependencies: $.grep( dependencies, function ( module ) {
1431                                                         var state = mw.loader.getState( module );
1432                                                         return state === 'registered' || state === 'loaded' || state === 'loading' || state === 'executing';
1433                                                 } ),
1434                                                 ready: ready,
1435                                                 error: error
1436                                         } );
1437                                 }
1438
1439                                 $.each( dependencies, function ( idx, module ) {
1440                                         var state = mw.loader.getState( module );
1441                                         // Only queue modules that are still in the initial 'registered' state
1442                                         // (not ones already loading, ready or error).
1443                                         if ( state === 'registered' && $.inArray( module, queue ) === -1 ) {
1444                                                 // Private modules must be embedded in the page. Don't bother queuing
1445                                                 // these as the server will deny them anyway (T101806).
1446                                                 if ( registry[ module ].group === 'private' ) {
1447                                                         registry[ module ].state = 'error';
1448                                                         handlePending( module );
1449                                                         return;
1450                                                 }
1451                                                 queue.push( module );
1452                                         }
1453                                 } );
1454
1455                                 mw.loader.work();
1456                         }
1457
1458                         function sortQuery( o ) {
1459                                 var key,
1460                                         sorted = {},
1461                                         a = [];
1462
1463                                 for ( key in o ) {
1464                                         if ( hasOwn.call( o, key ) ) {
1465                                                 a.push( key );
1466                                         }
1467                                 }
1468                                 a.sort();
1469                                 for ( key = 0; key < a.length; key++ ) {
1470                                         sorted[ a[ key ] ] = o[ a[ key ] ];
1471                                 }
1472                                 return sorted;
1473                         }
1474
1475                         /**
1476                          * Converts a module map of the form { foo: [ 'bar', 'baz' ], bar: [ 'baz, 'quux' ] }
1477                          * to a query string of the form foo.bar,baz|bar.baz,quux
1478                          *
1479                          * @private
1480                          */
1481                         function buildModulesString( moduleMap ) {
1482                                 var p, prefix,
1483                                         arr = [];
1484
1485                                 for ( prefix in moduleMap ) {
1486                                         p = prefix === '' ? '' : prefix + '.';
1487                                         arr.push( p + moduleMap[ prefix ].join( ',' ) );
1488                                 }
1489                                 return arr.join( '|' );
1490                         }
1491
1492                         /**
1493                          * Load modules from load.php
1494                          *
1495                          * @private
1496                          * @param {Object} moduleMap Module map, see #buildModulesString
1497                          * @param {Object} currReqBase Object with other parameters (other than 'modules') to use in the request
1498                          * @param {string} sourceLoadScript URL of load.php
1499                          */
1500                         function doRequest( moduleMap, currReqBase, sourceLoadScript ) {
1501                                 var request = $.extend(
1502                                         { modules: buildModulesString( moduleMap ) },
1503                                         currReqBase
1504                                 );
1505                                 request = sortQuery( request );
1506                                 addScript( sourceLoadScript + '?' + $.param( request ) );
1507                         }
1508
1509                         /**
1510                          * Resolve indexed dependencies.
1511                          *
1512                          * ResourceLoader uses an optimization to save space which replaces module names in
1513                          * dependency lists with the index of that module within the array of module
1514                          * registration data if it exists. The benefit is a significant reduction in the data
1515                          * size of the startup module. This function changes those dependency lists back to
1516                          * arrays of strings.
1517                          *
1518                          * @param {Array} modules Modules array
1519                          */
1520                         function resolveIndexedDependencies( modules ) {
1521                                 $.each( modules, function ( idx, module ) {
1522                                         if ( module[ 2 ] ) {
1523                                                 module[ 2 ] = $.map( module[ 2 ], function ( dep ) {
1524                                                         return typeof dep === 'number' ? modules[ dep ][ 0 ] : dep;
1525                                                 } );
1526                                         }
1527                                 } );
1528                         }
1529
1530                         /* Public Members */
1531                         return {
1532                                 /**
1533                                  * The module registry is exposed as an aid for debugging and inspecting page
1534                                  * state; it is not a public interface for modifying the registry.
1535                                  *
1536                                  * @see #registry
1537                                  * @property
1538                                  * @private
1539                                  */
1540                                 moduleRegistry: registry,
1541
1542                                 /**
1543                                  * @inheritdoc #newStyleTag
1544                                  * @method
1545                                  */
1546                                 addStyleTag: newStyleTag,
1547
1548                                 /**
1549                                  * Batch-request queued dependencies from the server.
1550                                  */
1551                                 work: function () {
1552                                         var     reqBase, splits, maxQueryLength, q, b, bSource, bGroup, bSourceGroup,
1553                                                 source, concatSource, origBatch, group, i, modules, sourceLoadScript,
1554                                                 currReqBase, currReqBaseLength, moduleMap, l,
1555                                                 lastDotIndex, prefix, suffix, bytesAdded;
1556
1557                                         // Build a list of request parameters common to all requests.
1558                                         reqBase = {
1559                                                 skin: mw.config.get( 'skin' ),
1560                                                 lang: mw.config.get( 'wgUserLanguage' ),
1561                                                 debug: mw.config.get( 'debug' )
1562                                         };
1563                                         // Split module batch by source and by group.
1564                                         splits = {};
1565                                         maxQueryLength = mw.config.get( 'wgResourceLoaderMaxQueryLength', 2000 );
1566
1567                                         // Appends a list of modules from the queue to the batch
1568                                         for ( q = 0; q < queue.length; q++ ) {
1569                                                 // Only request modules which are registered
1570                                                 if ( hasOwn.call( registry, queue[ q ] ) && registry[ queue[ q ] ].state === 'registered' ) {
1571                                                         // Prevent duplicate entries
1572                                                         if ( $.inArray( queue[ q ], batch ) === -1 ) {
1573                                                                 batch.push( queue[ q ] );
1574                                                                 // Mark registered modules as loading
1575                                                                 registry[ queue[ q ] ].state = 'loading';
1576                                                         }
1577                                                 }
1578                                         }
1579
1580                                         mw.loader.store.init();
1581                                         if ( mw.loader.store.enabled ) {
1582                                                 concatSource = [];
1583                                                 origBatch = batch;
1584                                                 batch = $.grep( batch, function ( module ) {
1585                                                         var source = mw.loader.store.get( module );
1586                                                         if ( source ) {
1587                                                                 concatSource.push( source );
1588                                                                 return false;
1589                                                         }
1590                                                         return true;
1591                                                 } );
1592                                                 try {
1593                                                         $.globalEval( concatSource.join( ';' ) );
1594                                                 } catch ( err ) {
1595                                                         // Not good, the cached mw.loader.implement calls failed! This should
1596                                                         // never happen, barring ResourceLoader bugs, browser bugs and PEBKACs.
1597                                                         // Depending on how corrupt the string is, it is likely that some
1598                                                         // modules' implement() succeeded while the ones after the error will
1599                                                         // never run and leave their modules in the 'loading' state forever.
1600
1601                                                         // Since this is an error not caused by an individual module but by
1602                                                         // something that infected the implement call itself, don't take any
1603                                                         // risks and clear everything in this cache.
1604                                                         mw.loader.store.clear();
1605                                                         // Re-add the ones still pending back to the batch and let the server
1606                                                         // repopulate these modules to the cache.
1607                                                         // This means that at most one module will be useless (the one that had
1608                                                         // the error) instead of all of them.
1609                                                         mw.track( 'resourceloader.exception', { exception: err, source: 'store-eval' } );
1610                                                         origBatch = $.grep( origBatch, function ( module ) {
1611                                                                 return registry[ module ].state === 'loading';
1612                                                         } );
1613                                                         batch = batch.concat( origBatch );
1614                                                 }
1615                                         }
1616
1617                                         // Early exit if there's nothing to load...
1618                                         if ( !batch.length ) {
1619                                                 return;
1620                                         }
1621
1622                                         // The queue has been processed into the batch, clear up the queue.
1623                                         queue = [];
1624
1625                                         // Always order modules alphabetically to help reduce cache
1626                                         // misses for otherwise identical content.
1627                                         batch.sort();
1628
1629                                         // Split batch by source and by group.
1630                                         for ( b = 0; b < batch.length; b++ ) {
1631                                                 bSource = registry[ batch[ b ] ].source;
1632                                                 bGroup = registry[ batch[ b ] ].group;
1633                                                 if ( !hasOwn.call( splits, bSource ) ) {
1634                                                         splits[ bSource ] = {};
1635                                                 }
1636                                                 if ( !hasOwn.call( splits[ bSource ], bGroup ) ) {
1637                                                         splits[ bSource ][ bGroup ] = [];
1638                                                 }
1639                                                 bSourceGroup = splits[ bSource ][ bGroup ];
1640                                                 bSourceGroup.push( batch[ b ] );
1641                                         }
1642
1643                                         // Clear the batch - this MUST happen before we append any
1644                                         // script elements to the body or it's possible that a script
1645                                         // will be locally cached, instantly load, and work the batch
1646                                         // again, all before we've cleared it causing each request to
1647                                         // include modules which are already loaded.
1648                                         batch = [];
1649
1650                                         for ( source in splits ) {
1651
1652                                                 sourceLoadScript = sources[ source ];
1653
1654                                                 for ( group in splits[ source ] ) {
1655
1656                                                         // Cache access to currently selected list of
1657                                                         // modules for this group from this source.
1658                                                         modules = splits[ source ][ group ];
1659
1660                                                         currReqBase = $.extend( {
1661                                                                 version: getCombinedVersion( modules )
1662                                                         }, reqBase );
1663                                                         // For user modules append a user name to the request.
1664                                                         if ( group === 'user' && mw.config.get( 'wgUserName' ) !== null ) {
1665                                                                 currReqBase.user = mw.config.get( 'wgUserName' );
1666                                                         }
1667                                                         currReqBaseLength = $.param( currReqBase ).length;
1668                                                         // We may need to split up the request to honor the query string length limit,
1669                                                         // so build it piece by piece.
1670                                                         l = currReqBaseLength + 9; // '&modules='.length == 9
1671
1672                                                         moduleMap = {}; // { prefix: [ suffixes ] }
1673
1674                                                         for ( i = 0; i < modules.length; i++ ) {
1675                                                                 // Determine how many bytes this module would add to the query string
1676                                                                 lastDotIndex = modules[ i ].lastIndexOf( '.' );
1677
1678                                                                 // If lastDotIndex is -1, substr() returns an empty string
1679                                                                 prefix = modules[ i ].substr( 0, lastDotIndex );
1680                                                                 suffix = modules[ i ].slice( lastDotIndex + 1 );
1681
1682                                                                 bytesAdded = hasOwn.call( moduleMap, prefix )
1683                                                                         ? suffix.length + 3 // '%2C'.length == 3
1684                                                                         : modules[ i ].length + 3; // '%7C'.length == 3
1685
1686                                                                 // If the request would become too long, create a new one,
1687                                                                 // but don't create empty requests
1688                                                                 if ( maxQueryLength > 0 && !$.isEmptyObject( moduleMap ) && l + bytesAdded > maxQueryLength ) {
1689                                                                         // This request would become too long, create a new one
1690                                                                         // and fire off the old one
1691                                                                         doRequest( moduleMap, currReqBase, sourceLoadScript );
1692                                                                         moduleMap = {};
1693                                                                         l = currReqBaseLength + 9;
1694                                                                         mw.track( 'resourceloader.splitRequest', { maxQueryLength: maxQueryLength } );
1695                                                                 }
1696                                                                 if ( !hasOwn.call( moduleMap, prefix ) ) {
1697                                                                         moduleMap[ prefix ] = [];
1698                                                                 }
1699                                                                 moduleMap[ prefix ].push( suffix );
1700                                                                 l += bytesAdded;
1701                                                         }
1702                                                         // If there's anything left in moduleMap, request that too
1703                                                         if ( !$.isEmptyObject( moduleMap ) ) {
1704                                                                 doRequest( moduleMap, currReqBase, sourceLoadScript );
1705                                                         }
1706                                                 }
1707                                         }
1708                                 },
1709
1710                                 /**
1711                                  * Register a source.
1712                                  *
1713                                  * The #work() method will use this information to split up requests by source.
1714                                  *
1715                                  *     mw.loader.addSource( 'mediawikiwiki', '//www.mediawiki.org/w/load.php' );
1716                                  *
1717                                  * @param {string|Object} id Source ID, or object mapping ids to load urls
1718                                  * @param {string} loadUrl Url to a load.php end point
1719                                  * @throws {Error} If source id is already registered
1720                                  */
1721                                 addSource: function ( id, loadUrl ) {
1722                                         var source;
1723                                         // Allow multiple additions
1724                                         if ( typeof id === 'object' ) {
1725                                                 for ( source in id ) {
1726                                                         mw.loader.addSource( source, id[ source ] );
1727                                                 }
1728                                                 return;
1729                                         }
1730
1731                                         if ( hasOwn.call( sources, id ) ) {
1732                                                 throw new Error( 'source already registered: ' + id );
1733                                         }
1734
1735                                         sources[ id ] = loadUrl;
1736                                 },
1737
1738                                 /**
1739                                  * Register a module, letting the system know about it and its properties.
1740                                  *
1741                                  * The startup modules contain calls to this method.
1742                                  *
1743                                  * When using multiple module registration by passing an array, dependencies that
1744                                  * are specified as references to modules within the array will be resolved before
1745                                  * the modules are registered.
1746                                  *
1747                                  * @param {string|Array} module Module name or array of arrays, each containing
1748                                  *  a list of arguments compatible with this method
1749                                  * @param {string|number} version Module version hash (falls backs to empty string)
1750                                  *  Can also be a number (timestamp) for compatibility with MediaWiki 1.25 and earlier.
1751                                  * @param {string|Array|Function} dependencies One string or array of strings of module
1752                                  *  names on which this module depends, or a function that returns that array.
1753                                  * @param {string} [group=null] Group which the module is in
1754                                  * @param {string} [source='local'] Name of the source
1755                                  * @param {string} [skip=null] Script body of the skip function
1756                                  */
1757                                 register: function ( module, version, dependencies, group, source, skip ) {
1758                                         var i;
1759                                         // Allow multiple registration
1760                                         if ( typeof module === 'object' ) {
1761                                                 resolveIndexedDependencies( module );
1762                                                 for ( i = 0; i < module.length; i++ ) {
1763                                                         // module is an array of module names
1764                                                         if ( typeof module[ i ] === 'string' ) {
1765                                                                 mw.loader.register( module[ i ] );
1766                                                         // module is an array of arrays
1767                                                         } else if ( typeof module[ i ] === 'object' ) {
1768                                                                 mw.loader.register.apply( mw.loader, module[ i ] );
1769                                                         }
1770                                                 }
1771                                                 return;
1772                                         }
1773                                         if ( hasOwn.call( registry, module ) ) {
1774                                                 throw new Error( 'module already registered: ' + module );
1775                                         }
1776                                         // List the module as registered
1777                                         registry[ module ] = {
1778                                                 // Exposed to execute() for mw.loader.implement() closures.
1779                                                 // Import happens via require().
1780                                                 module: {
1781                                                         exports: {}
1782                                                 },
1783                                                 version: version !== undefined ? String( version ) : '',
1784                                                 dependencies: [],
1785                                                 group: typeof group === 'string' ? group : null,
1786                                                 source: typeof source === 'string' ? source : 'local',
1787                                                 state: 'registered',
1788                                                 skip: typeof skip === 'string' ? skip : null
1789                                         };
1790                                         if ( typeof dependencies === 'string' ) {
1791                                                 // Allow dependencies to be given as a single module name
1792                                                 registry[ module ].dependencies = [ dependencies ];
1793                                         } else if ( typeof dependencies === 'object' || $.isFunction( dependencies ) ) {
1794                                                 // Allow dependencies to be given as an array of module names
1795                                                 // or a function which returns an array
1796                                                 registry[ module ].dependencies = dependencies;
1797                                         }
1798                                 },
1799
1800                                 /**
1801                                  * Implement a module given the components that make up the module.
1802                                  *
1803                                  * When #load or #using requests one or more modules, the server
1804                                  * response contain calls to this function.
1805                                  *
1806                                  * @param {string} module Name of module
1807                                  * @param {Function|Array} [script] Function with module code or Array of URLs to
1808                                  *  be used as the src attribute of a new `<script>` tag.
1809                                  * @param {Object} [style] Should follow one of the following patterns:
1810                                  *
1811                                  *     { "css": [css, ..] }
1812                                  *     { "url": { <media>: [url, ..] } }
1813                                  *
1814                                  * And for backwards compatibility (needs to be supported forever due to caching):
1815                                  *
1816                                  *     { <media>: css }
1817                                  *     { <media>: [url, ..] }
1818                                  *
1819                                  * The reason css strings are not concatenated anymore is bug 31676. We now check
1820                                  * whether it's safe to extend the stylesheet.
1821                                  *
1822                                  * @param {Object} [messages] List of key/value pairs to be added to mw#messages.
1823                                  * @param {Object} [templates] List of key/value pairs to be added to mw#templates.
1824                                  */
1825                                 implement: function ( module, script, style, messages, templates ) {
1826                                         // Automatically register module
1827                                         if ( !hasOwn.call( registry, module ) ) {
1828                                                 mw.loader.register( module );
1829                                         }
1830                                         // Check for duplicate implementation
1831                                         if ( hasOwn.call( registry, module ) && registry[ module ].script !== undefined ) {
1832                                                 throw new Error( 'module already implemented: ' + module );
1833                                         }
1834                                         // Attach components
1835                                         registry[ module ].script = script || null;
1836                                         registry[ module ].style = style || null;
1837                                         registry[ module ].messages = messages || null;
1838                                         registry[ module ].templates = templates || null;
1839                                         // The module may already have been marked as erroneous
1840                                         if ( $.inArray( registry[ module ].state, [ 'error', 'missing' ] ) === -1 ) {
1841                                                 registry[ module ].state = 'loaded';
1842                                                 if ( allReady( registry[ module ].dependencies ) ) {
1843                                                         execute( module );
1844                                                 }
1845                                         }
1846                                 },
1847
1848                                 /**
1849                                  * Execute a function as soon as one or more required modules are ready.
1850                                  *
1851                                  * Example of inline dependency on OOjs:
1852                                  *
1853                                  *     mw.loader.using( 'oojs', function () {
1854                                  *         OO.compare( [ 1 ], [ 1 ] );
1855                                  *     } );
1856                                  *
1857                                  * @param {string|Array} dependencies Module name or array of modules names the
1858                                  *  callback depends on to be ready before executing
1859                                  * @param {Function} [ready] Callback to execute when all dependencies are ready
1860                                  * @param {Function} [error] Callback to execute if one or more dependencies failed
1861                                  * @return {jQuery.Promise}
1862                                  * @since 1.23 this returns a promise
1863                                  */
1864                                 using: function ( dependencies, ready, error ) {
1865                                         var deferred = $.Deferred();
1866
1867                                         // Allow calling with a single dependency as a string
1868                                         if ( typeof dependencies === 'string' ) {
1869                                                 dependencies = [ dependencies ];
1870                                         }
1871
1872                                         if ( ready ) {
1873                                                 deferred.done( ready );
1874                                         }
1875                                         if ( error ) {
1876                                                 deferred.fail( error );
1877                                         }
1878
1879                                         // Resolve entire dependency map
1880                                         dependencies = resolve( dependencies );
1881                                         if ( allReady( dependencies ) ) {
1882                                                 // Run ready immediately
1883                                                 deferred.resolve();
1884                                         } else if ( anyFailed( dependencies ) ) {
1885                                                 // Execute error immediately if any dependencies have errors
1886                                                 deferred.reject(
1887                                                         new Error( 'One or more dependencies failed to load' ),
1888                                                         dependencies
1889                                                 );
1890                                         } else {
1891                                                 // Not all dependencies are ready: queue up a request
1892                                                 request( dependencies, deferred.resolve, deferred.reject );
1893                                         }
1894
1895                                         return deferred.promise();
1896                                 },
1897
1898                                 /**
1899                                  * Load an external script or one or more modules.
1900                                  *
1901                                  * @param {string|Array} modules Either the name of a module, array of modules,
1902                                  *  or a URL of an external script or style
1903                                  * @param {string} [type='text/javascript'] MIME type to use if calling with a URL of an
1904                                  *  external script or style; acceptable values are "text/css" and
1905                                  *  "text/javascript"; if no type is provided, text/javascript is assumed.
1906                                  */
1907                                 load: function ( modules, type ) {
1908                                         var filtered, l;
1909
1910                                         // Allow calling with a url or single dependency as a string
1911                                         if ( typeof modules === 'string' ) {
1912                                                 // "https://example.org/x.js", "http://example.org/x.js", "//example.org/x.js", "/x.js"
1913                                                 if ( /^(https?:)?\/?\//.test( modules ) ) {
1914                                                         if ( type === 'text/css' ) {
1915                                                                 // Support: IE 7-8
1916                                                                 // Use properties instead of attributes as IE throws security
1917                                                                 // warnings when inserting a <link> tag with a protocol-relative
1918                                                                 // URL set though attributes - when on HTTPS. See bug 41331.
1919                                                                 l = document.createElement( 'link' );
1920                                                                 l.rel = 'stylesheet';
1921                                                                 l.href = modules;
1922                                                                 $( 'head' ).append( l );
1923                                                                 return;
1924                                                         }
1925                                                         if ( type === 'text/javascript' || type === undefined ) {
1926                                                                 addScript( modules );
1927                                                                 return;
1928                                                         }
1929                                                         // Unknown type
1930                                                         throw new Error( 'invalid type for external url, must be text/css or text/javascript. not ' + type );
1931                                                 }
1932                                                 // Called with single module
1933                                                 modules = [ modules ];
1934                                         }
1935
1936                                         // Filter out undefined modules, otherwise resolve() will throw
1937                                         // an exception for trying to load an undefined module.
1938                                         // Undefined modules are acceptable here in load(), because load() takes
1939                                         // an array of unrelated modules, whereas the modules passed to
1940                                         // using() are related and must all be loaded.
1941                                         filtered = $.grep( modules, function ( module ) {
1942                                                 var state = mw.loader.getState( module );
1943                                                 return state !== null && state !== 'error' && state !== 'missing';
1944                                         } );
1945
1946                                         if ( filtered.length === 0 ) {
1947                                                 return;
1948                                         }
1949                                         // Resolve entire dependency map
1950                                         filtered = resolve( filtered );
1951                                         // If all modules are ready, or if any modules have errors, nothing to be done.
1952                                         if ( allReady( filtered ) || anyFailed( filtered ) ) {
1953                                                 return;
1954                                         }
1955                                         // Since some modules are not yet ready, queue up a request.
1956                                         request( filtered, undefined, undefined );
1957                                 },
1958
1959                                 /**
1960                                  * Change the state of one or more modules.
1961                                  *
1962                                  * @param {string|Object} module Module name or object of module name/state pairs
1963                                  * @param {string} state State name
1964                                  */
1965                                 state: function ( module, state ) {
1966                                         var m;
1967
1968                                         if ( typeof module === 'object' ) {
1969                                                 for ( m in module ) {
1970                                                         mw.loader.state( m, module[ m ] );
1971                                                 }
1972                                                 return;
1973                                         }
1974                                         if ( !hasOwn.call( registry, module ) ) {
1975                                                 mw.loader.register( module );
1976                                         }
1977                                         if ( $.inArray( state, [ 'ready', 'error', 'missing' ] ) !== -1
1978                                                 && registry[ module ].state !== state ) {
1979                                                 // Make sure pending modules depending on this one get executed if their
1980                                                 // dependencies are now fulfilled!
1981                                                 registry[ module ].state = state;
1982                                                 handlePending( module );
1983                                         } else {
1984                                                 registry[ module ].state = state;
1985                                         }
1986                                 },
1987
1988                                 /**
1989                                  * Get the version of a module.
1990                                  *
1991                                  * @param {string} module Name of module
1992                                  * @return {string|null} The version, or null if the module (or its version) is not
1993                                  *  in the registry.
1994                                  */
1995                                 getVersion: function ( module ) {
1996                                         if ( !hasOwn.call( registry, module ) || registry[ module ].version === undefined ) {
1997                                                 return null;
1998                                         }
1999                                         return registry[ module ].version;
2000                                 },
2001
2002                                 /**
2003                                  * Get the state of a module.
2004                                  *
2005                                  * @param {string} module Name of module
2006                                  * @return {string|null} The state, or null if the module (or its state) is not
2007                                  *  in the registry.
2008                                  */
2009                                 getState: function ( module ) {
2010                                         if ( !hasOwn.call( registry, module ) || registry[ module ].state === undefined ) {
2011                                                 return null;
2012                                         }
2013                                         return registry[ module ].state;
2014                                 },
2015
2016                                 /**
2017                                  * Get the names of all registered modules.
2018                                  *
2019                                  * @return {Array}
2020                                  */
2021                                 getModuleNames: function () {
2022                                         return $.map( registry, function ( i, key ) {
2023                                                 return key;
2024                                         } );
2025                                 },
2026
2027                                 /**
2028                                  * Get the exported value of a module.
2029                                  *
2030                                  * Module provide this value via their local `module.exports`.
2031                                  *
2032                                  * @since 1.27
2033                                  * @return {Array}
2034                                  */
2035                                 require: function ( moduleName ) {
2036                                         var state = mw.loader.getState( moduleName );
2037
2038                                         // Only ready modules can be required
2039                                         if ( state !== 'ready' ) {
2040                                                 // Module may've forgotten to declare a dependency
2041                                                 throw new Error( 'Module "' + moduleName + '" is not loaded.' );
2042                                         }
2043
2044                                         return registry[ moduleName ].module.exports;
2045                                 },
2046
2047                                 /**
2048                                  * @inheritdoc mw.inspect#runReports
2049                                  * @method
2050                                  */
2051                                 inspect: function () {
2052                                         var args = slice.call( arguments );
2053                                         mw.loader.using( 'mediawiki.inspect', function () {
2054                                                 mw.inspect.runReports.apply( mw.inspect, args );
2055                                         } );
2056                                 },
2057
2058                                 /**
2059                                  * On browsers that implement the localStorage API, the module store serves as a
2060                                  * smart complement to the browser cache. Unlike the browser cache, the module store
2061                                  * can slice a concatenated response from ResourceLoader into its constituent
2062                                  * modules and cache each of them separately, using each module's versioning scheme
2063                                  * to determine when the cache should be invalidated.
2064                                  *
2065                                  * @singleton
2066                                  * @class mw.loader.store
2067                                  */
2068                                 store: {
2069                                         // Whether the store is in use on this page.
2070                                         enabled: null,
2071
2072                                         MODULE_SIZE_MAX: 100 * 1000,
2073
2074                                         // The contents of the store, mapping '[module name]@[version]' keys
2075                                         // to module implementations.
2076                                         items: {},
2077
2078                                         // Cache hit stats
2079                                         stats: { hits: 0, misses: 0, expired: 0 },
2080
2081                                         /**
2082                                          * Construct a JSON-serializable object representing the content of the store.
2083                                          *
2084                                          * @return {Object} Module store contents.
2085                                          */
2086                                         toJSON: function () {
2087                                                 return { items: mw.loader.store.items, vary: mw.loader.store.getVary() };
2088                                         },
2089
2090                                         /**
2091                                          * Get the localStorage key for the entire module store. The key references
2092                                          * $wgDBname to prevent clashes between wikis which share a common host.
2093                                          *
2094                                          * @return {string} localStorage item key
2095                                          */
2096                                         getStoreKey: function () {
2097                                                 return 'MediaWikiModuleStore:' + mw.config.get( 'wgDBname' );
2098                                         },
2099
2100                                         /**
2101                                          * Get a key on which to vary the module cache.
2102                                          *
2103                                          * @return {string} String of concatenated vary conditions.
2104                                          */
2105                                         getVary: function () {
2106                                                 return [
2107                                                         mw.config.get( 'skin' ),
2108                                                         mw.config.get( 'wgResourceLoaderStorageVersion' ),
2109                                                         mw.config.get( 'wgUserLanguage' )
2110                                                 ].join( ':' );
2111                                         },
2112
2113                                         /**
2114                                          * Get a key for a specific module. The key format is '[name]@[version]'.
2115                                          *
2116                                          * @param {string} module Module name
2117                                          * @return {string|null} Module key or null if module does not exist
2118                                          */
2119                                         getModuleKey: function ( module ) {
2120                                                 return hasOwn.call( registry, module ) ?
2121                                                         ( module + '@' + registry[ module ].version ) : null;
2122                                         },
2123
2124                                         /**
2125                                          * Initialize the store.
2126                                          *
2127                                          * Retrieves store from localStorage and (if successfully retrieved) decoding
2128                                          * the stored JSON value to a plain object.
2129                                          *
2130                                          * The try / catch block is used for JSON & localStorage feature detection.
2131                                          * See the in-line documentation for Modernizr's localStorage feature detection
2132                                          * code for a full account of why we need a try / catch:
2133                                          * <https://github.com/Modernizr/Modernizr/blob/v2.7.1/modernizr.js#L771-L796>.
2134                                          */
2135                                         init: function () {
2136                                                 var raw, data;
2137
2138                                                 if ( mw.loader.store.enabled !== null ) {
2139                                                         // Init already ran
2140                                                         return;
2141                                                 }
2142
2143                                                 if (
2144                                                         // Disabled because localStorage quotas are tight and (in Firefox's case)
2145                                                         // shared by multiple origins.
2146                                                         // See T66721, and <https://bugzilla.mozilla.org/show_bug.cgi?id=1064466>.
2147                                                         /Firefox|Opera/.test( navigator.userAgent ) ||
2148
2149                                                         // Disabled by configuration.
2150                                                         !mw.config.get( 'wgResourceLoaderStorageEnabled' )
2151                                                 ) {
2152                                                         // Clear any previous store to free up space. (T66721)
2153                                                         mw.loader.store.clear();
2154                                                         mw.loader.store.enabled = false;
2155                                                         return;
2156                                                 }
2157                                                 if ( mw.config.get( 'debug' ) ) {
2158                                                         // Disable module store in debug mode
2159                                                         mw.loader.store.enabled = false;
2160                                                         return;
2161                                                 }
2162
2163                                                 try {
2164                                                         raw = localStorage.getItem( mw.loader.store.getStoreKey() );
2165                                                         // If we get here, localStorage is available; mark enabled
2166                                                         mw.loader.store.enabled = true;
2167                                                         data = JSON.parse( raw );
2168                                                         if ( data && typeof data.items === 'object' && data.vary === mw.loader.store.getVary() ) {
2169                                                                 mw.loader.store.items = data.items;
2170                                                                 return;
2171                                                         }
2172                                                 } catch ( e ) {
2173                                                         mw.track( 'resourceloader.exception', { exception: e, source: 'store-localstorage-init' } );
2174                                                 }
2175
2176                                                 if ( raw === undefined ) {
2177                                                         // localStorage failed; disable store
2178                                                         mw.loader.store.enabled = false;
2179                                                 } else {
2180                                                         mw.loader.store.update();
2181                                                 }
2182                                         },
2183
2184                                         /**
2185                                          * Retrieve a module from the store and update cache hit stats.
2186                                          *
2187                                          * @param {string} module Module name
2188                                          * @return {string|boolean} Module implementation or false if unavailable
2189                                          */
2190                                         get: function ( module ) {
2191                                                 var key;
2192
2193                                                 if ( !mw.loader.store.enabled ) {
2194                                                         return false;
2195                                                 }
2196
2197                                                 key = mw.loader.store.getModuleKey( module );
2198                                                 if ( key in mw.loader.store.items ) {
2199                                                         mw.loader.store.stats.hits++;
2200                                                         return mw.loader.store.items[ key ];
2201                                                 }
2202                                                 mw.loader.store.stats.misses++;
2203                                                 return false;
2204                                         },
2205
2206                                         /**
2207                                          * Stringify a module and queue it for storage.
2208                                          *
2209                                          * @param {string} module Module name
2210                                          * @param {Object} descriptor The module's descriptor as set in the registry
2211                                          */
2212                                         set: function ( module, descriptor ) {
2213                                                 var args, key, src;
2214
2215                                                 if ( !mw.loader.store.enabled ) {
2216                                                         return false;
2217                                                 }
2218
2219                                                 key = mw.loader.store.getModuleKey( module );
2220
2221                                                 if (
2222                                                         // Already stored a copy of this exact version
2223                                                         key in mw.loader.store.items ||
2224                                                         // Module failed to load
2225                                                         descriptor.state !== 'ready' ||
2226                                                         // Unversioned, private, or site-/user-specific
2227                                                         ( !descriptor.version || $.inArray( descriptor.group, [ 'private', 'user' ] ) !== -1 ) ||
2228                                                         // Partial descriptor
2229                                                         $.inArray( undefined, [ descriptor.script, descriptor.style,
2230                                                                         descriptor.messages, descriptor.templates ] ) !== -1
2231                                                 ) {
2232                                                         // Decline to store
2233                                                         return false;
2234                                                 }
2235
2236                                                 try {
2237                                                         args = [
2238                                                                 JSON.stringify( module ),
2239                                                                 typeof descriptor.script === 'function' ?
2240                                                                         String( descriptor.script ) :
2241                                                                         JSON.stringify( descriptor.script ),
2242                                                                 JSON.stringify( descriptor.style ),
2243                                                                 JSON.stringify( descriptor.messages ),
2244                                                                 JSON.stringify( descriptor.templates )
2245                                                         ];
2246                                                         // Attempted workaround for a possible Opera bug (bug T59567).
2247                                                         // This regex should never match under sane conditions.
2248                                                         if ( /^\s*\(/.test( args[ 1 ] ) ) {
2249                                                                 args[ 1 ] = 'function' + args[ 1 ];
2250                                                                 mw.track( 'resourceloader.assert', { source: 'bug-T59567' } );
2251                                                         }
2252                                                 } catch ( e ) {
2253                                                         mw.track( 'resourceloader.exception', { exception: e, source: 'store-localstorage-json' } );
2254                                                         return;
2255                                                 }
2256
2257                                                 src = 'mw.loader.implement(' + args.join( ',' ) + ');';
2258                                                 if ( src.length > mw.loader.store.MODULE_SIZE_MAX ) {
2259                                                         return false;
2260                                                 }
2261                                                 mw.loader.store.items[ key ] = src;
2262                                                 mw.loader.store.update();
2263                                         },
2264
2265                                         /**
2266                                          * Iterate through the module store, removing any item that does not correspond
2267                                          * (in name and version) to an item in the module registry.
2268                                          */
2269                                         prune: function () {
2270                                                 var key, module;
2271
2272                                                 if ( !mw.loader.store.enabled ) {
2273                                                         return false;
2274                                                 }
2275
2276                                                 for ( key in mw.loader.store.items ) {
2277                                                         module = key.slice( 0, key.indexOf( '@' ) );
2278                                                         if ( mw.loader.store.getModuleKey( module ) !== key ) {
2279                                                                 mw.loader.store.stats.expired++;
2280                                                                 delete mw.loader.store.items[ key ];
2281                                                         } else if ( mw.loader.store.items[ key ].length > mw.loader.store.MODULE_SIZE_MAX ) {
2282                                                                 // This value predates the enforcement of a size limit on cached modules.
2283                                                                 delete mw.loader.store.items[ key ];
2284                                                         }
2285                                                 }
2286                                         },
2287
2288                                         /**
2289                                          * Clear the entire module store right now.
2290                                          */
2291                                         clear: function () {
2292                                                 mw.loader.store.items = {};
2293                                                 try {
2294                                                         localStorage.removeItem( mw.loader.store.getStoreKey() );
2295                                                 } catch ( ignored ) {}
2296                                         },
2297
2298                                         /**
2299                                          * Sync in-memory store back to localStorage.
2300                                          *
2301                                          * This function debounces updates. When called with a flush already pending,
2302                                          * the call is coalesced into the pending update. The call to
2303                                          * localStorage.setItem will be naturally deferred until the page is quiescent.
2304                                          *
2305                                          * Because localStorage is shared by all pages from the same origin, if multiple
2306                                          * pages are loaded with different module sets, the possibility exists that
2307                                          * modules saved by one page will be clobbered by another. But the impact would
2308                                          * be minor and the problem would be corrected by subsequent page views.
2309                                          *
2310                                          * @method
2311                                          */
2312                                         update: ( function () {
2313                                                 var hasPendingWrite = false;
2314
2315                                                 function flushWrites() {
2316                                                         var data, key;
2317                                                         if ( !hasPendingWrite || !mw.loader.store.enabled ) {
2318                                                                 return;
2319                                                         }
2320
2321                                                         mw.loader.store.prune();
2322                                                         key = mw.loader.store.getStoreKey();
2323                                                         try {
2324                                                                 // Replacing the content of the module store might fail if the new
2325                                                                 // contents would exceed the browser's localStorage size limit. To
2326                                                                 // avoid clogging the browser with stale data, always remove the old
2327                                                                 // value before attempting to set the new one.
2328                                                                 localStorage.removeItem( key );
2329                                                                 data = JSON.stringify( mw.loader.store );
2330                                                                 localStorage.setItem( key, data );
2331                                                         } catch ( e ) {
2332                                                                 mw.track( 'resourceloader.exception', { exception: e, source: 'store-localstorage-update' } );
2333                                                         }
2334
2335                                                         hasPendingWrite = false;
2336                                                 }
2337
2338                                                 return function () {
2339                                                         if ( !hasPendingWrite ) {
2340                                                                 hasPendingWrite = true;
2341                                                                 mw.requestIdleCallback( flushWrites );
2342                                                         }
2343                                                 };
2344                                         }() )
2345                                 }
2346                         };
2347                 }() ),
2348
2349                 /**
2350                  * HTML construction helper functions
2351                  *
2352                  *     @example
2353                  *
2354                  *     var Html, output;
2355                  *
2356                  *     Html = mw.html;
2357                  *     output = Html.element( 'div', {}, new Html.Raw(
2358                  *         Html.element( 'img', { src: '<' } )
2359                  *     ) );
2360                  *     mw.log( output ); // <div><img src="&lt;"/></div>
2361                  *
2362                  * @class mw.html
2363                  * @singleton
2364                  */
2365                 html: ( function () {
2366                         function escapeCallback( s ) {
2367                                 switch ( s ) {
2368                                         case '\'':
2369                                                 return '&#039;';
2370                                         case '"':
2371                                                 return '&quot;';
2372                                         case '<':
2373                                                 return '&lt;';
2374                                         case '>':
2375                                                 return '&gt;';
2376                                         case '&':
2377                                                 return '&amp;';
2378                                 }
2379                         }
2380
2381                         return {
2382                                 /**
2383                                  * Escape a string for HTML.
2384                                  *
2385                                  * Converts special characters to HTML entities.
2386                                  *
2387                                  *     mw.html.escape( '< > \' & "' );
2388                                  *     // Returns &lt; &gt; &#039; &amp; &quot;
2389                                  *
2390                                  * @param {string} s The string to escape
2391                                  * @return {string} HTML
2392                                  */
2393                                 escape: function ( s ) {
2394                                         return s.replace( /['"<>&]/g, escapeCallback );
2395                                 },
2396
2397                                 /**
2398                                  * Create an HTML element string, with safe escaping.
2399                                  *
2400                                  * @param {string} name The tag name.
2401                                  * @param {Object} [attrs] An object with members mapping element names to values
2402                                  * @param {string|mw.html.Raw|mw.html.Cdata|null} [contents=null] The contents of the element.
2403                                  *
2404                                  *  - string: Text to be escaped.
2405                                  *  - null: The element is treated as void with short closing form, e.g. `<br/>`.
2406                                  *  - this.Raw: The raw value is directly included.
2407                                  *  - this.Cdata: The raw value is directly included. An exception is
2408                                  *    thrown if it contains any illegal ETAGO delimiter.
2409                                  *    See <http://www.w3.org/TR/html401/appendix/notes.html#h-B.3.2>.
2410                                  * @return {string} HTML
2411                                  */
2412                                 element: function ( name, attrs, contents ) {
2413                                         var v, attrName, s = '<' + name;
2414
2415                                         if ( attrs ) {
2416                                                 for ( attrName in attrs ) {
2417                                                         v = attrs[ attrName ];
2418                                                         // Convert name=true, to name=name
2419                                                         if ( v === true ) {
2420                                                                 v = attrName;
2421                                                         // Skip name=false
2422                                                         } else if ( v === false ) {
2423                                                                 continue;
2424                                                         }
2425                                                         s += ' ' + attrName + '="' + this.escape( String( v ) ) + '"';
2426                                                 }
2427                                         }
2428                                         if ( contents === undefined || contents === null ) {
2429                                                 // Self close tag
2430                                                 s += '/>';
2431                                                 return s;
2432                                         }
2433                                         // Regular open tag
2434                                         s += '>';
2435                                         switch ( typeof contents ) {
2436                                                 case 'string':
2437                                                         // Escaped
2438                                                         s += this.escape( contents );
2439                                                         break;
2440                                                 case 'number':
2441                                                 case 'boolean':
2442                                                         // Convert to string
2443                                                         s += String( contents );
2444                                                         break;
2445                                                 default:
2446                                                         if ( contents instanceof this.Raw ) {
2447                                                                 // Raw HTML inclusion
2448                                                                 s += contents.value;
2449                                                         } else if ( contents instanceof this.Cdata ) {
2450                                                                 // CDATA
2451                                                                 if ( /<\/[a-zA-z]/.test( contents.value ) ) {
2452                                                                         throw new Error( 'mw.html.element: Illegal end tag found in CDATA' );
2453                                                                 }
2454                                                                 s += contents.value;
2455                                                         } else {
2456                                                                 throw new Error( 'mw.html.element: Invalid type of contents' );
2457                                                         }
2458                                         }
2459                                         s += '</' + name + '>';
2460                                         return s;
2461                                 },
2462
2463                                 /**
2464                                  * Wrapper object for raw HTML passed to mw.html.element().
2465                                  *
2466                                  * @class mw.html.Raw
2467                                  */
2468                                 Raw: function ( value ) {
2469                                         this.value = value;
2470                                 },
2471
2472                                 /**
2473                                  * Wrapper object for CDATA element contents passed to mw.html.element()
2474                                  *
2475                                  * @class mw.html.Cdata
2476                                  */
2477                                 Cdata: function ( value ) {
2478                                         this.value = value;
2479                                 }
2480                         };
2481                 }() ),
2482
2483                 // Skeleton user object, extended by the 'mediawiki.user' module.
2484                 /**
2485                  * @class mw.user
2486                  * @singleton
2487                  */
2488                 user: {
2489                         /**
2490                          * @property {mw.Map}
2491                          */
2492                         options: new Map(),
2493                         /**
2494                          * @property {mw.Map}
2495                          */
2496                         tokens: new Map()
2497                 },
2498
2499                 // OOUI widgets specific to MediaWiki
2500                 widgets: {},
2501
2502                 /**
2503                  * Registry and firing of events.
2504                  *
2505                  * MediaWiki has various interface components that are extended, enhanced
2506                  * or manipulated in some other way by extensions, gadgets and even
2507                  * in core itself.
2508                  *
2509                  * This framework helps streamlining the timing of when these other
2510                  * code paths fire their plugins (instead of using document-ready,
2511                  * which can and should be limited to firing only once).
2512                  *
2513                  * Features like navigating to other wiki pages, previewing an edit
2514                  * and editing itself – without a refresh – can then retrigger these
2515                  * hooks accordingly to ensure everything still works as expected.
2516                  *
2517                  * Example usage:
2518                  *
2519                  *     mw.hook( 'wikipage.content' ).add( fn ).remove( fn );
2520                  *     mw.hook( 'wikipage.content' ).fire( $content );
2521                  *
2522                  * Handlers can be added and fired for arbitrary event names at any time. The same
2523                  * event can be fired multiple times. The last run of an event is memorized
2524                  * (similar to `$(document).ready` and `$.Deferred().done`).
2525                  * This means if an event is fired, and a handler added afterwards, the added
2526                  * function will be fired right away with the last given event data.
2527                  *
2528                  * Like Deferreds and Promises, the mw.hook object is both detachable and chainable.
2529                  * Thus allowing flexible use and optimal maintainability and authority control.
2530                  * You can pass around the `add` and/or `fire` method to another piece of code
2531                  * without it having to know the event name (or `mw.hook` for that matter).
2532                  *
2533                  *     var h = mw.hook( 'bar.ready' );
2534                  *     new mw.Foo( .. ).fetch( { callback: h.fire } );
2535                  *
2536                  * Note: Events are documented with an underscore instead of a dot in the event
2537                  * name due to jsduck not supporting dots in that position.
2538                  *
2539                  * @class mw.hook
2540                  */
2541                 hook: ( function () {
2542                         var lists = {};
2543
2544                         /**
2545                          * Create an instance of mw.hook.
2546                          *
2547                          * @method hook
2548                          * @member mw
2549                          * @param {string} name Name of hook.
2550                          * @return {mw.hook}
2551                          */
2552                         return function ( name ) {
2553                                 var list = hasOwn.call( lists, name ) ?
2554                                         lists[ name ] :
2555                                         lists[ name ] = $.Callbacks( 'memory' );
2556
2557                                 return {
2558                                         /**
2559                                          * Register a hook handler
2560                                          *
2561                                          * @param {...Function} handler Function to bind.
2562                                          * @chainable
2563                                          */
2564                                         add: list.add,
2565
2566                                         /**
2567                                          * Unregister a hook handler
2568                                          *
2569                                          * @param {...Function} handler Function to unbind.
2570                                          * @chainable
2571                                          */
2572                                         remove: list.remove,
2573
2574                                         /**
2575                                          * Run a hook.
2576                                          *
2577                                          * @param {...Mixed} data
2578                                          * @chainable
2579                                          */
2580                                         fire: function () {
2581                                                 return list.fireWith.call( this, null, slice.call( arguments ) );
2582                                         }
2583                                 };
2584                         };
2585                 }() )
2586         };
2587
2588         // Alias $j to jQuery for backwards compatibility
2589         // @deprecated since 1.23 Use $ or jQuery instead
2590         mw.log.deprecate( window, '$j', $, 'Use $ or jQuery instead.' );
2591
2592         /**
2593          * Log a message to window.console, if possible.
2594          *
2595          * Useful to force logging of some errors that are otherwise hard to detect (i.e., this logs
2596          * also in production mode). Gets console references in each invocation instead of caching the
2597          * reference, so that debugging tools loaded later are supported (e.g. Firebug Lite in IE).
2598          *
2599          * @private
2600          * @method log_
2601          * @param {string} topic Stream name passed by mw.track
2602          * @param {Object} data Data passed by mw.track
2603          * @param {Error} [data.exception]
2604          * @param {string} data.source Error source
2605          * @param {string} [data.module] Name of module which caused the error
2606          */
2607         function log( topic, data ) {
2608                 var msg,
2609                         e = data.exception,
2610                         source = data.source,
2611                         module = data.module,
2612                         console = window.console;
2613
2614                 if ( console && console.log ) {
2615                         msg = ( e ? 'Exception' : 'Error' ) + ' in ' + source;
2616                         if ( module ) {
2617                                 msg += ' in module ' + module;
2618                         }
2619                         msg += ( e ? ':' : '.' );
2620                         console.log( msg );
2621
2622                         // If we have an exception object, log it to the error channel to trigger
2623                         // proper stacktraces in browsers that support it. No fallback as we have
2624                         // no browsers that don't support error(), but do support log().
2625                         if ( e && console.error ) {
2626                                 console.error( String( e ), e );
2627                         }
2628                 }
2629         }
2630
2631         // Subscribe to error streams
2632         mw.trackSubscribe( 'resourceloader.exception', log );
2633         mw.trackSubscribe( 'resourceloader.assert', log );
2634
2635         /**
2636          * Fired when all modules associated with the page have finished loading.
2637          *
2638          * @event resourceloader_loadEnd
2639          * @member mw.hook
2640          */
2641         $( function () {
2642                 var loading = $.grep( mw.loader.getModuleNames(), function ( module ) {
2643                         return mw.loader.getState( module ) === 'loading';
2644                 } );
2645                 // In order to use jQuery.when (which stops early if one of the promises got rejected)
2646                 // cast any loading failures into successes. We only need a callback, not the module.
2647                 loading = $.map( loading, function ( module ) {
2648                         return mw.loader.using( module ).then( null, function () {
2649                                 return $.Deferred().resolve();
2650                         } );
2651                 } );
2652                 $.when.apply( $, loading ).then( function () {
2653                         mwPerformance.mark( 'mwLoadEnd' );
2654                         mw.hook( 'resourceloader.loadEnd' ).fire();
2655                 } );
2656         } );
2657
2658         // Attach to window and globally alias
2659         window.mw = window.mediaWiki = mw;
2660 }( jQuery ) );