resources/src/startup/startup.js

   1 /**
   2  * This file is where we decide whether to initialise the Grade A run-time.
   3  *
   4  * - Beware: This file MUST parse without errors on even the most ancient of browsers!
   5  */
   6 /* eslint-disable no-implicit-globals */
   7 /* global $VARS, $CODE, RLQ:true, NORLQ:true */
   8
   9 /**
  10  * See <https://www.mediawiki.org/wiki/Compatibility#Browsers>
  11  *
  12  * Capabilities required for modern run-time:
  13  * - ECMAScript 5
  14  * - DOM Level 4 & Selectors API Level 1
  15  * - HTML5 & Web Storage
  16  * - DOM Level 2 Events
  17  *
  18  * Browsers we support in our modern run-time (Grade A):
  19  * - Chrome 13+
  20  * - IE 11+
  21  * - Firefox 4+
  22  * - Safari 5+
  23  * - Opera 15+
  24  * - Mobile Safari 6.0+ (iOS 6+)
  25  * - Android 4.1+
  26  *
  27  * Browsers we support in our no-javascript run-time (Grade C):
  28  * - Chrome 1+
  29  * - IE 6+
  30  * - Firefox 3+
  31  * - Safari 3+
  32  * - Opera 15+
  33  * - Mobile Safari 5.0+ (iOS 4+)
  34  * - Android 2.0+
  35  * - WebOS < 1.5
  36  * - PlayStation
  37  * - Symbian-based browsers
  38  * - NetFront-based browser
  39  * - Opera Mini
  40  * - Nokia's Ovi Browser
  41  * - MeeGo's browser
  42  * - Google Glass
  43  * - UC Mini (speed mode on)
  44  *
  45  * Other browsers that pass the check are considered Grade X.
  46  *
  47  * @private
  48  * @param {string} ua User agent string
  49  * @return {boolean} User agent is compatible with MediaWiki JS
  50  */
  51 function isCompatible( ua ) {
  52         return !!(
  53                 // https://caniuse.com/#feat=es5
  54                 // https://caniuse.com/#feat=use-strict
  55                 // https://caniuse.com/#feat=json / https://phabricator.wikimedia.org/T141344#2784065
  56                 ( function () {
  57                         'use strict';
  58                         return !this && Function.prototype.bind && window.JSON;
  59                 }() ) &&
  60
  61                 // https://caniuse.com/#feat=queryselector
  62                 'querySelector' in document &&
  63
  64                 // https://caniuse.com/#feat=namevalue-storage
  65                 // https://developer.blackberry.com/html5/apis/v1_0/localstorage.html
  66                 // https://blog.whatwg.org/this-week-in-html-5-episode-30
  67                 'localStorage' in window &&
  68
  69                 // https://caniuse.com/#feat=addeventlistener
  70                 'addEventListener' in window &&
  71
  72                 // Hardcoded exceptions for browsers that pass the requirement but we don't
  73                 // want to support in the modern run-time.
  74                 //
  75                 // Please extend the regex instead of adding new ones!
  76                 // And add a test case to startup.test.js
  77                 !ua.match( /MSIE 10|webOS\/1\.[0-4]|SymbianOS|NetFront|Opera Mini|S40OviBrowser|MeeGo|Android.+Glass|^Mozilla\/5\.0 .+ Gecko\/$|googleweblight|PLAYSTATION|PlayStation/ )
  78         );
  79 }
  80
  81 if ( !isCompatible( navigator.userAgent ) ) {
  82         // Handle Grade C
  83         // Undo speculative Grade A <html> class. See ResourceLoaderClientHtml::getDocumentAttributes().
  84         document.documentElement.className = document.documentElement.className
  85                 .replace( /(^|\s)client-js(\s|$)/, '$1client-nojs$2' );
  86
  87         // Process any callbacks for Grade C
  88         while ( window.NORLQ && NORLQ[ 0 ] ) {
  89                 NORLQ.shift()();
  90         }
  91         NORLQ = {
  92                 push: function ( fn ) {
  93                         fn();
  94                 }
  95         };
  96
  97         // Clear and disable the Grade A queue
  98         RLQ = {
  99                 push: function () {}
 100         };
 101 } else {
 102         // Handle Grade A
 103
 104         if ( window.performance && performance.mark ) {
 105                 performance.mark( 'mwStartup' );
 106         }
 107
 108         // This embeds mediawiki.js, which defines 'mw' and 'mw.loader'.
 109         $CODE.defineLoader();
 110
 111         /**
 112          * The $CODE and $VARS placeholders are substituted in ResourceLoaderStartUpModule.php.
 113          */
 114         ( function () {
 115                 /* global mw */
 116                 mw.config = new mw.Map( $VARS.wgLegacyJavaScriptGlobals );
 117
 118                 $CODE.registrations();
 119
 120                 mw.config.set( $VARS.configuration );
 121                 // For the current page
 122                 mw.config.set( window.RLCONF || {} );
 123                 mw.loader.state( window.RLSTATE || {} );
 124                 mw.loader.load( window.RLPAGEMODULES || [] );
 125
 126                 // Process RLQ callbacks
 127                 //
 128                 // The code in these callbacks could've been exposed from load.php and
 129                 // requested client-side. Instead, they are pushed by the server directly
 130                 // (from ResourceLoaderClientHtml and other parts of MediaWiki). This
 131                 // saves the need for additional round trips. It also allows load.php
 132                 // to remain stateless and sending personal data in the HTML instead.
 133                 //
 134                 // The HTML inline script lazy-defines the 'RLQ' array. Now that we are
 135                 // processing it, replace it with an implementation where 'push' actually
 136                 // considers executing the code directly. This is to ensure any late
 137                 // arrivals will also be processed. Late arrival can happen because
 138                 // startup.js is executed asynchronously, concurrently with the streaming
 139                 // response of the HTML.
 140                 RLQ = window.RLQ || [];
 141                 RLQ.push = function ( fn ) {
 142                         if ( typeof fn === 'function' ) {
 143                                 fn();
 144                         } else {
 145                                 // If the first parameter is not a function, then it is an array
 146                                 // containing a list of required module names and a function.
 147                                 // Do an actual push for now, as this signature is handled
 148                                 // later by mediawiki.base.js.
 149                                 RLQ[ RLQ.length ] = fn;
 150                         }
 151                 };
 152                 while ( RLQ[ 0 ] ) {
 153                         // Process all values gathered so far
 154                         RLQ.push( RLQ.shift() );
 155                 }
 156
 157                 // Clear and disable the Grade C queue
 158                 NORLQ = {
 159                         push: function () {}
 160                 };
 161         }() );
 162 }