From: Timo Tijhof <krinklemail@gmail.com>
Date: Wed, 11 Sep 2019 04:46:50 +0000 (+0100)
Subject: mediawiki.util: Add debounce() function
X-Git-Tag: 1.34.0-rc.0~259^2
X-Git-Url: http://git.cyclocoop.org/%22%20.%20generer_url_aide%28?a=commitdiff_plain;h=a6827329000ec584a2614a167c79616c08c21ce7;p=lhc%2Fweb%2Fwiklou.git

mediawiki.util: Add debounce() function

Bug: T213426
Change-Id: If370b959b2617d0f506ac3ed344af8c6a667e70d
---

diff --git a/resources/Resources.php b/resources/Resources.php
index 80770221f8..0960e83961 100644
--- a/resources/Resources.php
+++ b/resources/Resources.php
@@ -940,6 +940,9 @@ return [
 		'scripts' => [
 			'resources/src/mediawiki.htmlform.checker.js',
 		],
+		'dependencies' => [
+			'mediawiki.util',
+		],
 		'targets' => [ 'desktop', 'mobile' ],
 	],
 	'mediawiki.htmlform.ooui' => [
diff --git a/resources/src/mediawiki.htmlform.checker.js b/resources/src/mediawiki.htmlform.checker.js
index 33207d49a7..473635a53e 100644
--- a/resources/src/mediawiki.htmlform.checker.js
+++ b/resources/src/mediawiki.htmlform.checker.js
@@ -3,14 +3,6 @@
 	// FIXME: mw.htmlform.Element also sets this to empty object
 	mw.htmlform = {};
 
-	function debounce( delay, callback ) {
-		var timeout;
-		return function () {
-			clearTimeout( timeout );
-			timeout = setTimeout( Function.prototype.apply.bind( callback, this, arguments ), delay );
-		};
-	}
-
 	/**
 	 * @class mw.htmlform.Checker
 	 */
@@ -60,7 +52,7 @@
 		if ( $extraElements ) {
 			$e = $e.add( $extraElements );
 		}
-		$e.on( events, debounce( 1000, this.validate.bind( this ) ) );
+		$e.on( events, mw.util.debounce( 1000, this.validate.bind( this ) ) );
 
 		return this;
 	};
diff --git a/resources/src/mediawiki.util/util.js b/resources/src/mediawiki.util/util.js
index 57843cb976..85216649e0 100644
--- a/resources/src/mediawiki.util/util.js
+++ b/resources/src/mediawiki.util/util.js
@@ -83,6 +83,27 @@ util = {
 		return escapeIdInternal( str, config.FragmentMode[ 0 ] );
 	},
 
+	/**
+	 * Return a wrapper function that is debounced for the given duration.
+	 *
+	 * When it is first called, a timeout is scheduled. If before the timer
+	 * is reached the wrapper is called again, it gets rescheduled for the
+	 * same duration from now until it stops being called. The original function
+	 * is called from the "tail" of such chain, with the last set of arguments.
+	 *
+	 * @since 1.34
+	 * @param {number} delay Time in milliseconds
+	 * @param {Function} callback
+	 * @return {Function}
+	 */
+	debounce: function ( delay, callback ) {
+		var timeout;
+		return function () {
+			clearTimeout( timeout );
+			timeout = setTimeout( Function.prototype.apply.bind( callback, this, arguments ), delay );
+		};
+	},
+
 	/**
 	 * Encode page titles for use in a URL
 	 *
diff --git a/tests/qunit/suites/resources/mediawiki/mediawiki.util.test.js b/tests/qunit/suites/resources/mediawiki/mediawiki.util.test.js
index 4f61abd186..a05b50b462 100644
--- a/tests/qunit/suites/resources/mediawiki/mediawiki.util.test.js
+++ b/tests/qunit/suites/resources/mediawiki/mediawiki.util.test.js
@@ -474,4 +474,27 @@
 
 		assert.strictEqual( mw.util.escapeRegExp( normal ), normal, 'Alphanumerals are left alone' );
 	} );
+
+	QUnit.test( 'debounce', function ( assert ) {
+		var fn,
+			q = [],
+			done = assert.async();
+
+		fn = mw.util.debounce( 0, function ( data ) {
+			q.push( data );
+		} );
+
+		fn( 1 );
+		fn( 2 );
+		fn( 3 );
+
+		setTimeout( function () {
+			assert.deepEqual(
+				q,
+				[ 3 ],
+				'Last one ran'
+			);
+			done();
+		} );
+	} );
 }() );