resources/src/mediawiki.rcfilters/mw.rcfilters.Controller.js

   1 ( function ( mw, $ ) {
   2         /* eslint no-underscore-dangle: "off" */
   3         /**
   4          * Controller for the filters in Recent Changes
   5          *
   6          * @param {mw.rcfilters.dm.FiltersViewModel} filtersModel Filters view model
   7          * @param {mw.rcfilters.dm.ChangesListViewModel} changesListModel Changes list view model
   8          * @param {mw.rcfilters.dm.SavedQueriesModel} savedQueriesModel Saved queries model
   9          */
  10         mw.rcfilters.Controller = function MwRcfiltersController( filtersModel, changesListModel, savedQueriesModel ) {
  11                 this.filtersModel = filtersModel;
  12                 this.changesListModel = changesListModel;
  13                 this.savedQueriesModel = savedQueriesModel;
  14                 this.requestCounter = 0;
  15                 this.baseFilterState = {};
  16                 this.uriProcessor = null;
  17                 this.initializing = false;
  18         };
  19
  20         /* Initialization */
  21         OO.initClass( mw.rcfilters.Controller );
  22
  23         /**
  24          * Initialize the filter and parameter states
  25          *
  26          * @param {Array} filterStructure Filter definition and structure for the model
  27          * @param {Object} [namespaceStructure] Namespace definition
  28          */
  29         mw.rcfilters.Controller.prototype.initialize = function ( filterStructure, namespaceStructure ) {
  30                 var parsedSavedQueries,
  31                         uri = new mw.Uri(),
  32                         $changesList = $( '.mw-changeslist' ).first().contents();
  33
  34                 // Initialize the model
  35                 this.filtersModel.initializeFilters( filterStructure, namespaceStructure );
  36                 this._buildBaseFilterState();
  37
  38                 this.uriProcessor = new mw.rcfilters.UriProcessor(
  39                         this.filtersModel
  40                 );
  41
  42                 try {
  43                         parsedSavedQueries = JSON.parse( mw.user.options.get( 'rcfilters-saved-queries' ) || '{}' );
  44                 } catch ( err ) {
  45                         parsedSavedQueries = {};
  46                 }
  47
  48                 // The queries are saved in a minimized state, so we need
  49                 // to send over the base state so the saved queries model
  50                 // can normalize them per each query item
  51                 this.savedQueriesModel.initialize(
  52                         parsedSavedQueries,
  53                         this._getBaseFilterState()
  54                 );
  55
  56                 // Check whether we need to load defaults.
  57                 // We do this by checking whether the current URI query
  58                 // contains any parameters recognized by the system.
  59                 // If it does, we load the given state.
  60                 // If it doesn't, we have no values at all, and we assume
  61                 // the user loads the base-page and we load defaults.
  62                 // Defaults should only be applied on load (if necessary)
  63                 // or on request
  64                 this.initializing = true;
  65                 if (
  66                         this.savedQueriesModel.getDefault() &&
  67                         !this.uriProcessor.doesQueryContainRecognizedParams( uri.query )
  68                 ) {
  69                         // We have defaults from a saved query.
  70                         // We will load them straight-forward (as if
  71                         // they were clicked in the menu) so we trigger
  72                         // a full ajax request and change of URL
  73                         this.applySavedQuery( this.savedQueriesModel.getDefault() );
  74                 } else {
  75                         // There are either recognized parameters in the URL
  76                         // or there are none, but there is also no default
  77                         // saved query (so defaults are from the backend)
  78                         // We want to update the state but not fetch results
  79                         // again
  80                         this.updateStateFromUrl( false );
  81
  82                         // Update the changes list with the existing data
  83                         // so it gets processed
  84                         this.changesListModel.update(
  85                                 $changesList.length ? $changesList : 'NO_RESULTS',
  86                                 $( 'fieldset.rcoptions' ).first()
  87                         );
  88                 }
  89
  90                 this.initializing = false;
  91                 this.switchView( 'default' );
  92         };
  93
  94         /**
  95          * Switch the view of the filters model
  96          *
  97          * @param {string} view Requested view
  98          */
  99         mw.rcfilters.Controller.prototype.switchView = function ( view ) {
 100                 this.filtersModel.switchView( view );
 101         };
 102
 103         /**
 104          * Reset to default filters
 105          */
 106         mw.rcfilters.Controller.prototype.resetToDefaults = function () {
 107                 this.uriProcessor.updateModelBasedOnQuery( this._getDefaultParams() );
 108                 this.updateChangesList();
 109         };
 110
 111         /**
 112          * Empty all selected filters
 113          */
 114         mw.rcfilters.Controller.prototype.emptyFilters = function () {
 115                 var highlightedFilterNames = this.filtersModel
 116                         .getHighlightedItems()
 117                         .map( function ( filterItem ) { return { name: filterItem.getName() }; } );
 118
 119                 this.filtersModel.emptyAllFilters();
 120                 this.filtersModel.clearAllHighlightColors();
 121                 // Check all filter interactions
 122                 this.filtersModel.reassessFilterInteractions();
 123
 124                 this.updateChangesList();
 125
 126                 if ( highlightedFilterNames ) {
 127                         this._trackHighlight( 'clearAll', highlightedFilterNames );
 128                 }
 129         };
 130
 131         /**
 132          * Update the selected state of a filter
 133          *
 134          * @param {string} filterName Filter name
 135          * @param {boolean} [isSelected] Filter selected state
 136          */
 137         mw.rcfilters.Controller.prototype.toggleFilterSelect = function ( filterName, isSelected ) {
 138                 var filterItem = this.filtersModel.getItemByName( filterName );
 139
 140                 if ( !filterItem ) {
 141                         // If no filter was found, break
 142                         return;
 143                 }
 144
 145                 isSelected = isSelected === undefined ? !filterItem.isSelected() : isSelected;
 146
 147                 if ( filterItem.isSelected() !== isSelected ) {
 148                         this.filtersModel.toggleFilterSelected( filterName, isSelected );
 149
 150                         this.updateChangesList();
 151
 152                         // Check filter interactions
 153                         this.filtersModel.reassessFilterInteractions( filterItem );
 154                 }
 155         };
 156
 157         /**
 158          * Clear both highlight and selection of a filter
 159          *
 160          * @param {string} filterName Name of the filter item
 161          */
 162         mw.rcfilters.Controller.prototype.clearFilter = function ( filterName ) {
 163                 var filterItem = this.filtersModel.getItemByName( filterName ),
 164                         isHighlighted = filterItem.isHighlighted();
 165
 166                 if ( filterItem.isSelected() || isHighlighted ) {
 167                         this.filtersModel.clearHighlightColor( filterName );
 168                         this.filtersModel.toggleFilterSelected( filterName, false );
 169                         this.updateChangesList();
 170                         this.filtersModel.reassessFilterInteractions( filterItem );
 171                 }
 172
 173                 if ( isHighlighted ) {
 174                         this._trackHighlight( 'clear', filterName );
 175                 }
 176         };
 177
 178         /**
 179          * Toggle the highlight feature on and off
 180          */
 181         mw.rcfilters.Controller.prototype.toggleHighlight = function () {
 182                 this.filtersModel.toggleHighlight();
 183                 this._updateURL();
 184
 185                 if ( this.filtersModel.isHighlightEnabled() ) {
 186                         mw.hook( 'RcFilters.highlight.enable' ).fire();
 187                 }
 188         };
 189
 190         /**
 191          * Toggle the namespaces inverted feature on and off
 192          */
 193         mw.rcfilters.Controller.prototype.toggleInvertedNamespaces = function () {
 194                 this.filtersModel.toggleInvertedNamespaces();
 195                 this.updateChangesList();
 196         };
 197
 198         /**
 199          * Set the highlight color for a filter item
 200          *
 201          * @param {string} filterName Name of the filter item
 202          * @param {string} color Selected color
 203          */
 204         mw.rcfilters.Controller.prototype.setHighlightColor = function ( filterName, color ) {
 205                 this.filtersModel.setHighlightColor( filterName, color );
 206                 this._updateURL();
 207                 this._trackHighlight( 'set', { name: filterName, color: color } );
 208         };
 209
 210         /**
 211          * Clear highlight for a filter item
 212          *
 213          * @param {string} filterName Name of the filter item
 214          */
 215         mw.rcfilters.Controller.prototype.clearHighlightColor = function ( filterName ) {
 216                 this.filtersModel.clearHighlightColor( filterName );
 217                 this._updateURL();
 218                 this._trackHighlight( 'clear', filterName );
 219         };
 220
 221         /**
 222          * Save the current model state as a saved query
 223          *
 224          * @param {string} [label] Label of the saved query
 225          */
 226         mw.rcfilters.Controller.prototype.saveCurrentQuery = function ( label ) {
 227                 var highlightedItems = {},
 228                         highlightEnabled = this.filtersModel.isHighlightEnabled();
 229
 230                 // Prepare highlights
 231                 this.filtersModel.getHighlightedItems().forEach( function ( item ) {
 232                         highlightedItems[ item.getName() ] = highlightEnabled ?
 233                                 item.getHighlightColor() : null;
 234                 } );
 235                 // These are filter states; highlight is stored as boolean
 236                 highlightedItems.highlight = this.filtersModel.isHighlightEnabled();
 237
 238                 // Add item
 239                 this.savedQueriesModel.addNewQuery(
 240                         label || mw.msg( 'rcfilters-savedqueries-defaultlabel' ),
 241                         {
 242                                 filters: this.filtersModel.getSelectedState(),
 243                                 highlights: highlightedItems,
 244                                 invert: this.filtersModel.areNamespacesInverted()
 245                         }
 246                 );
 247
 248                 // Save item
 249                 this._saveSavedQueries();
 250         };
 251
 252         /**
 253          * Remove a saved query
 254          *
 255          * @param {string} queryID Query id
 256          */
 257         mw.rcfilters.Controller.prototype.removeSavedQuery = function ( queryID ) {
 258                 var query = this.savedQueriesModel.getItemByID( queryID );
 259
 260                 this.savedQueriesModel.removeItems( [ query ] );
 261
 262                 // Check if this item was the default
 263                 if ( this.savedQueriesModel.getDefault() === queryID ) {
 264                         // Nulify the default
 265                         this.savedQueriesModel.setDefault( null );
 266                 }
 267                 this._saveSavedQueries();
 268         };
 269
 270         /**
 271          * Rename a saved query
 272          *
 273          * @param {string} queryID Query id
 274          * @param {string} newLabel New label for the query
 275          */
 276         mw.rcfilters.Controller.prototype.renameSavedQuery = function ( queryID, newLabel ) {
 277                 var queryItem = this.savedQueriesModel.getItemByID( queryID );
 278
 279                 if ( queryItem ) {
 280                         queryItem.updateLabel( newLabel );
 281                 }
 282                 this._saveSavedQueries();
 283         };
 284
 285         /**
 286          * Set a saved query as default
 287          *
 288          * @param {string} queryID Query Id. If null is given, default
 289          *  query is reset.
 290          */
 291         mw.rcfilters.Controller.prototype.setDefaultSavedQuery = function ( queryID ) {
 292                 this.savedQueriesModel.setDefault( queryID );
 293                 this._saveSavedQueries();
 294         };
 295
 296         /**
 297          * Load a saved query
 298          *
 299          * @param {string} queryID Query id
 300          */
 301         mw.rcfilters.Controller.prototype.applySavedQuery = function ( queryID ) {
 302                 var data, highlights,
 303                         queryItem = this.savedQueriesModel.getItemByID( queryID );
 304
 305                 if ( queryItem ) {
 306                         data = queryItem.getData();
 307                         highlights = data.highlights;
 308
 309                         // Backwards compatibility; initial version mispelled 'highlight' with 'highlights'
 310                         highlights.highlight = highlights.highlights || highlights.highlight;
 311
 312                         // Update model state from filters
 313                         this.filtersModel.toggleFiltersSelected( data.filters );
 314
 315                         // Update namespace inverted property
 316                         this.filtersModel.toggleInvertedNamespaces( !!Number( data.invert ) );
 317
 318                         // Update highlight state
 319                         this.filtersModel.toggleHighlight( !!Number( highlights.highlight ) );
 320                         this.filtersModel.getItems().forEach( function ( filterItem ) {
 321                                 var color = highlights[ filterItem.getName() ];
 322                                 if ( color ) {
 323                                         filterItem.setHighlightColor( color );
 324                                 } else {
 325                                         filterItem.clearHighlightColor();
 326                                 }
 327                         } );
 328
 329                         // Check all filter interactions
 330                         this.filtersModel.reassessFilterInteractions();
 331
 332                         this.updateChangesList();
 333                 }
 334         };
 335
 336         /**
 337          * Check whether the current filter and highlight state exists
 338          * in the saved queries model.
 339          *
 340          * @return {boolean} Query exists
 341          */
 342         mw.rcfilters.Controller.prototype.findQueryMatchingCurrentState = function () {
 343                 var highlightedItems = {};
 344
 345                 // Prepare highlights of the current query
 346                 this.filtersModel.getItemsSupportingHighlights().forEach( function ( item ) {
 347                         highlightedItems[ item.getName() ] = item.getHighlightColor();
 348                 } );
 349                 highlightedItems.highlight = this.filtersModel.isHighlightEnabled();
 350
 351                 return this.savedQueriesModel.findMatchingQuery(
 352                         {
 353                                 filters: this.filtersModel.getSelectedState(),
 354                                 highlights: highlightedItems,
 355                                 invert: this.filtersModel.areNamespacesInverted()
 356                         }
 357                 );
 358         };
 359
 360         /**
 361          * Get an object representing the base state of parameters
 362          * and highlights.
 363          *
 364          * This is meant to make sure that the saved queries that are
 365          * in memory are always the same structure as what we would get
 366          * by calling the current model's "getSelectedState" and by checking
 367          * highlight items.
 368          *
 369          * In cases where a user saved a query when the system had a certain
 370          * set of filters, and then a filter was added to the system, we want
 371          * to make sure that the stored queries can still be comparable to
 372          * the current state, which means that we need the base state for
 373          * two operations:
 374          *
 375          * - Saved queries are stored in "minimal" view (only changed filters
 376          *   are stored); When we initialize the system, we merge each minimal
 377          *   query with the base state (using 'getNormalizedFilters') so all
 378          *   saved queries have the exact same structure as what we would get
 379          *   by checking the getSelectedState of the filter.
 380          * - When we save the queries, we minimize the object to only represent
 381          *   whatever has actually changed, rather than store the entire
 382          *   object. To check what actually is different so we can store it,
 383          *   we need to obtain a base state to compare against, this is
 384          *   what #_getMinimalFilterList does
 385          */
 386         mw.rcfilters.Controller.prototype._buildBaseFilterState = function () {
 387                 var defaultParams = this.filtersModel.getDefaultParams(),
 388                         highlightedItems = {};
 389
 390                 // Prepare highlights
 391                 this.filtersModel.getItemsSupportingHighlights().forEach( function ( item ) {
 392                         highlightedItems[ item.getName() ] = null;
 393                 } );
 394                 highlightedItems.highlight = false;
 395
 396                 this.baseFilterState = {
 397                         filters: this.filtersModel.getFiltersFromParameters( defaultParams ),
 398                         highlights: highlightedItems,
 399                         invert: false
 400                 };
 401         };
 402
 403         /**
 404          * Get an object representing the base filter state of both
 405          * filters and highlights. The structure is similar to what we use
 406          * to store each query in the saved queries object:
 407          * {
 408          *    filters: {
 409          *        filterName: (bool)
 410          *    },
 411          *    highlights: {
 412          *        filterName: (string|null)
 413          *    }
 414          * }
 415          *
 416          * @return {Object} Object representing the base state of
 417          *  parameters and highlights
 418          */
 419         mw.rcfilters.Controller.prototype._getBaseFilterState = function () {
 420                 return this.baseFilterState;
 421         };
 422
 423         /**
 424          * Get an object that holds only the parameters and highlights that have
 425          * values different than the base default value.
 426          *
 427          * This is the reverse of the normalization we do initially on loading and
 428          * initializing the saved queries model.
 429          *
 430          * @param {Object} valuesObject Object representing the state of both
 431          *  filters and highlights in its normalized version, to be minimized.
 432          * @return {Object} Minimal filters and highlights list
 433          */
 434         mw.rcfilters.Controller.prototype._getMinimalFilterList = function ( valuesObject ) {
 435                 var result = { filters: {}, highlights: {} },
 436                         baseState = this._getBaseFilterState();
 437
 438                 // XOR results
 439                 $.each( valuesObject.filters, function ( name, value ) {
 440                         if ( baseState.filters !== undefined && baseState.filters[ name ] !== value ) {
 441                                 result.filters[ name ] = value;
 442                         }
 443                 } );
 444
 445                 $.each( valuesObject.highlights, function ( name, value ) {
 446                         if ( baseState.highlights !== undefined && baseState.highlights[ name ] !== value ) {
 447                                 result.highlights[ name ] = value;
 448                         }
 449                 } );
 450
 451                 return result;
 452         };
 453
 454         /**
 455          * Save the current state of the saved queries model with all
 456          * query item representation in the user settings.
 457          */
 458         mw.rcfilters.Controller.prototype._saveSavedQueries = function () {
 459                 var stringified,
 460                         state = this.savedQueriesModel.getState(),
 461                         controller = this;
 462
 463                 // Minimize before save
 464                 $.each( state.queries, function ( queryID, info ) {
 465                         state.queries[ queryID ].data = controller._getMinimalFilterList( info.data );
 466                 } );
 467
 468                 // Stringify state
 469                 stringified = JSON.stringify( state );
 470
 471                 if ( stringified.length > 65535 ) {
 472                         // Sanity check, since the preference can only hold that.
 473                         return;
 474                 }
 475
 476                 // Save the preference
 477                 new mw.Api().saveOption( 'rcfilters-saved-queries', stringified );
 478                 // Update the preference for this session
 479                 mw.user.options.set( 'rcfilters-saved-queries', stringified );
 480         };
 481
 482         /**
 483          * Synchronize the URL with the current state of the filters
 484          * without adding an history entry.
 485          */
 486         mw.rcfilters.Controller.prototype.replaceUrl = function () {
 487                 mw.rcfilters.UriProcessor.static.replaceState( this._getUpdatedUri() );
 488         };
 489
 490         /**
 491          * Update filter state (selection and highlighting) based
 492          * on current URL values.
 493          *
 494          * @param {boolean} [fetchChangesList=true] Fetch new results into the changes
 495          *  list based on the updated model.
 496          */
 497         mw.rcfilters.Controller.prototype.updateStateFromUrl = function ( fetchChangesList ) {
 498                 fetchChangesList = fetchChangesList === undefined ? true : !!fetchChangesList;
 499
 500                 this.uriProcessor.updateModelBasedOnQuery( new mw.Uri().query );
 501
 502                 // Only update and fetch new results if it is requested
 503                 if ( fetchChangesList ) {
 504                         this.updateChangesList();
 505                 }
 506         };
 507
 508         /**
 509          * Update the list of changes and notify the model
 510          *
 511          * @param {Object} [params] Extra parameters to add to the API call
 512          */
 513         mw.rcfilters.Controller.prototype.updateChangesList = function ( params ) {
 514                 this._updateURL( params );
 515                 this.changesListModel.invalidate();
 516                 this._fetchChangesList()
 517                         .then(
 518                                 // Success
 519                                 function ( pieces ) {
 520                                         var $changesListContent = pieces.changes,
 521                                                 $fieldset = pieces.fieldset;
 522                                         this.changesListModel.update( $changesListContent, $fieldset );
 523                                 }.bind( this )
 524                                 // Do nothing for failure
 525                         );
 526         };
 527
 528         /**
 529          * Get an object representing the default parameter state, whether
 530          * it is from the model defaults or from the saved queries.
 531          *
 532          * @return {Object} Default parameters
 533          */
 534         mw.rcfilters.Controller.prototype._getDefaultParams = function () {
 535                 var data, queryHighlights,
 536                         savedParams = {},
 537                         savedHighlights = {},
 538                         defaultSavedQueryItem = this.savedQueriesModel.getItemByID( this.savedQueriesModel.getDefault() );
 539
 540                 if ( mw.config.get( 'wgStructuredChangeFiltersEnableSaving' ) &&
 541                         defaultSavedQueryItem ) {
 542
 543                         data = defaultSavedQueryItem.getData();
 544
 545                         queryHighlights = data.highlights || {};
 546                         savedParams = this.filtersModel.getParametersFromFilters( data.filters || {} );
 547
 548                         // Translate highlights to parameters
 549                         savedHighlights.highlight = String( Number( queryHighlights.highlight ) );
 550                         $.each( queryHighlights, function ( filterName, color ) {
 551                                 if ( filterName !== 'highlights' ) {
 552                                         savedHighlights[ filterName + '_color' ] = color;
 553                                 }
 554                         } );
 555
 556                         return $.extend( true, {}, savedParams, savedHighlights, { invert: data.invert } );
 557                 }
 558
 559                 return $.extend(
 560                         { highlight: '0' },
 561                         this.filtersModel.getDefaultParams()
 562                 );
 563         };
 564
 565         /**
 566          * Get an object representing the default parameter state, whether
 567          * it is from the model defaults or from the saved queries.
 568          *
 569          * @return {Object} Default parameters
 570          */
 571         mw.rcfilters.Controller.prototype._getDefaultParams = function () {
 572                 var data, queryHighlights,
 573                         savedParams = {},
 574                         savedHighlights = {},
 575                         defaultSavedQueryItem = this.savedQueriesModel.getItemByID( this.savedQueriesModel.getDefault() );
 576
 577                 if ( mw.config.get( 'wgStructuredChangeFiltersEnableSaving' ) &&
 578                         defaultSavedQueryItem ) {
 579
 580                         data = defaultSavedQueryItem.getData();
 581
 582                         queryHighlights = data.highlights || {};
 583                         savedParams = this.filtersModel.getParametersFromFilters( data.filters || {} );
 584
 585                         // Translate highlights to parameters
 586                         savedHighlights.highlight = String( Number( queryHighlights.highlight ) );
 587                         $.each( queryHighlights, function ( filterName, color ) {
 588                                 if ( filterName !== 'highlights' ) {
 589                                         savedHighlights[ filterName + '_color' ] = color;
 590                                 }
 591                         } );
 592
 593                         return $.extend( true, {}, savedParams, savedHighlights );
 594                 }
 595
 596                 return this.filtersModel.getDefaultParams();
 597         };
 598
 599         /**
 600          * Update the URL of the page to reflect current filters
 601          *
 602          * This should not be called directly from outside the controller.
 603          * If an action requires changing the URL, it should either use the
 604          * highlighting actions below, or call #updateChangesList which does
 605          * the uri corrections already.
 606          *
 607          * @param {Object} [params] Extra parameters to add to the API call
 608          */
 609         mw.rcfilters.Controller.prototype._updateURL = function ( params ) {
 610                 var currentUri = new mw.Uri(),
 611                         updatedUri = this._getUpdatedUri();
 612
 613                 updatedUri.extend( params || {} );
 614
 615                 if (
 616                         this.uriProcessor.getVersion( currentUri.query ) !== 2 ||
 617                         this.uriProcessor.isNewState( currentUri.query, updatedUri.query )
 618                 ) {
 619                         if ( this.initializing ) {
 620                                 // Initially, when we just build the first page load
 621                                 // out of defaults, we want to replace the history
 622                                 mw.rcfilters.UriProcessor.static.replaceState( updatedUri );
 623                         } else {
 624                                 mw.rcfilters.UriProcessor.static.pushState( updatedUri );
 625                         }
 626                 }
 627         };
 628
 629         /**
 630          * Get an updated mw.Uri object based on the model state
 631          *
 632          * @return {mw.Uri} Updated Uri
 633          */
 634         mw.rcfilters.Controller.prototype._getUpdatedUri = function () {
 635                 var uri = new mw.Uri();
 636
 637                 // Minimize url
 638                 uri.query = this.uriProcessor.minimizeQuery(
 639                         $.extend(
 640                                 true,
 641                                 {},
 642                                 // We want to retain unrecognized params
 643                                 // The uri params from model will override
 644                                 // any recognized value in the current uri
 645                                 // query, retain unrecognized params, and
 646                                 // the result will then be minimized
 647                                 uri.query,
 648                                 this.uriProcessor.getUriParametersFromModel(),
 649                                 { urlversion: '2' }
 650                         )
 651                 );
 652
 653                 return uri;
 654         };
 655
 656         /**
 657          * Fetch the list of changes from the server for the current filters
 658          *
 659          * @return {jQuery.Promise} Promise object that will resolve with the changes list
 660          *  or with a string denoting no results.
 661          */
 662         mw.rcfilters.Controller.prototype._fetchChangesList = function () {
 663                 var uri = this._getUpdatedUri(),
 664                         requestId = ++this.requestCounter,
 665                         latestRequest = function () {
 666                                 return requestId === this.requestCounter;
 667                         }.bind( this );
 668
 669                 return $.ajax( uri.toString(), { contentType: 'html' } )
 670                         .then(
 671                                 // Success
 672                                 function ( html ) {
 673                                         var $parsed;
 674                                         if ( !latestRequest() ) {
 675                                                 return $.Deferred().reject();
 676                                         }
 677
 678                                         $parsed = $( $.parseHTML( html ) );
 679
 680                                         return {
 681                                                 // Changes list
 682                                                 changes: $parsed.find( '.mw-changeslist' ).first().contents(),
 683                                                 // Fieldset
 684                                                 fieldset: $parsed.find( 'fieldset.rcoptions' ).first()
 685                                         };
 686                                 },
 687                                 // Failure
 688                                 function ( responseObj ) {
 689                                         var $parsed;
 690
 691                                         if ( !latestRequest() ) {
 692                                                 return $.Deferred().reject();
 693                                         }
 694
 695                                         $parsed = $( $.parseHTML( responseObj.responseText ) );
 696
 697                                         // Force a resolve state to this promise
 698                                         return $.Deferred().resolve( {
 699                                                 changes: 'NO_RESULTS',
 700                                                 fieldset: $parsed.find( 'fieldset.rcoptions' ).first()
 701                                         } ).promise();
 702                                 }
 703                         );
 704         };
 705
 706         /**
 707          * Track usage of highlight feature
 708          *
 709          * @param {string} action
 710          * @param {array|object|string} filters
 711          */
 712         mw.rcfilters.Controller.prototype._trackHighlight = function ( action, filters ) {
 713                 filters = typeof filters === 'string' ? { name: filters } : filters;
 714                 filters = !Array.isArray( filters ) ? [ filters ] : filters;
 715                 mw.track(
 716                         'event.ChangesListHighlights',
 717                         {
 718                                 action: action,
 719                                 filters: filters,
 720                                 userId: mw.user.getId()
 721                         }
 722                 );
 723         };
 724
 725 }( mediaWiki, jQuery ) );