resources/mediawiki/mediawiki.inspect.js

   1 /*!
   2  * Tools for inspecting page composition and performance.
   3  *
   4  * @author Ori Livneh
   5  * @since 1.22
   6  */
   7 /*jshint devel:true */
   8 ( function ( mw, $ ) {
   9
  10         function sortByProperty( array, prop, descending ) {
  11                 var order = descending ? -1 : 1;
  12                 return array.sort( function ( a, b ) {
  13                         return a[prop] > b[prop] ? order : a[prop] < b[prop] ? -order : 0;
  14                 } );
  15         }
  16
  17         /**
  18          * @class mw.inspect
  19          * @singleton
  20          */
  21         var inspect = {
  22
  23                 /**
  24                  * Calculate the byte size of a ResourceLoader module.
  25                  *
  26                  * @param {string} moduleName The name of the module
  27                  * @return {number|null} Module size in bytes or null
  28                  */
  29                 getModuleSize: function ( moduleName ) {
  30                         var module = mw.loader.moduleRegistry[ moduleName ],
  31                                 payload = 0;
  32
  33                         if ( mw.loader.getState( moduleName ) !== 'ready' ) {
  34                                 return null;
  35                         }
  36
  37                         if ( !module.style && !module.script ) {
  38                                 return null;
  39                         }
  40
  41                         // Tally CSS
  42                         if ( module.style && $.isArray( module.style.css ) ) {
  43                                 $.each( module.style.css, function ( i, stylesheet ) {
  44                                         payload += $.byteLength( stylesheet );
  45                                 } );
  46                         }
  47
  48                         // Tally JavaScript
  49                         if ( $.isFunction( module.script ) ) {
  50                                 payload += $.byteLength( module.script.toString() );
  51                         }
  52
  53                         return payload;
  54                 },
  55
  56                 /**
  57                  * Given CSS source, count both the total number of selectors it
  58                  * contains and the number which match some element in the current
  59                  * document.
  60                  *
  61                  * @param {string} css CSS source
  62                  * @return Selector counts
  63                  * @return {number} return.selectors Total number of selectors
  64                  * @return {number} return.matched Number of matched selectors
  65                  */
  66                 auditSelectors: function ( css ) {
  67                         var selectors = { total: 0, matched: 0 },
  68                                 style = document.createElement( 'style' ),
  69                                 sheet, rules;
  70
  71                         style.textContent = css;
  72                         document.body.appendChild( style );
  73                         // Standards-compliant browsers use .sheet.cssRules, IE8 uses .styleSheet.rules…
  74                         sheet = style.sheet || style.styleSheet;
  75                         rules = sheet.cssRules || sheet.rules;
  76                         $.each( rules, function ( index, rule ) {
  77                                 selectors.total++;
  78                                 if ( document.querySelector( rule.selectorText ) !== null ) {
  79                                         selectors.matched++;
  80                                 }
  81                         } );
  82                         document.body.removeChild( style );
  83                         return selectors;
  84                 },
  85
  86                 /**
  87                  * Get a list of all loaded ResourceLoader modules.
  88                  *
  89                  * @return {Array} List of module names
  90                  */
  91                 getLoadedModules: function () {
  92                         return $.grep( mw.loader.getModuleNames(), function ( module ) {
  93                                 return mw.loader.getState( module ) === 'ready';
  94                         } );
  95                 },
  96
  97                 /**
  98                  * Print tabular data to the console, using console.table, console.log,
  99                  * or mw.log (in declining order of preference).
 100                  *
 101                  * @param {Array} data Tabular data represented as an array of objects
 102                  *  with common properties.
 103                  */
 104                 dumpTable: function ( data ) {
 105                         try {
 106                                 // Bartosz made me put this here.
 107                                 if ( window.opera ) { throw window.opera; }
 108                                 // Use Function.prototype#call to force an exception on Firefox,
 109                                 // which doesn't define console#table but doesn't complain if you
 110                                 // try to invoke it.
 111                                 console.table.call( console.table, data );
 112                                 return;
 113                         } catch (e) {}
 114                         try {
 115                                 console.log( $.toJSON( data, null, 2 ) );
 116                                 return;
 117                         } catch (e) {}
 118                         mw.log( data );
 119                 },
 120
 121                 /**
 122                  * Generate and print one more reports. When invoked with no arguments,
 123                  * print all reports.
 124                  *
 125                  * @param {string...} [reports] Report names to run, or unset to print
 126                  *  all available reports.
 127                  */
 128                 runReports: function () {
 129                         var reports = arguments.length > 0 ?
 130                                 Array.prototype.slice.call( arguments ) :
 131                                 $.map( inspect.reports, function ( v, k ) { return k; } );
 132
 133                         $.each( reports, function ( index, name ) {
 134                                 inspect.dumpTable( inspect.reports[name]() );
 135                         } );
 136                 },
 137
 138                 /**
 139                  * @class mw.inspect.reports
 140                  * @singleton
 141                  */
 142                 reports: {
 143                         /**
 144                          * Generate a breakdown of all loaded modules and their size in
 145                          * kilobytes. Modules are ordered from largest to smallest.
 146                          */
 147                         size: function () {
 148                                 // Map each module to a descriptor object.
 149                                 var modules = $.map( inspect.getLoadedModules(), function ( module ) {
 150                                         return {
 151                                                 name: module,
 152                                                 size: inspect.getModuleSize( module )
 153                                         };
 154                                 } );
 155
 156                                 // Sort module descriptors by size, largest first.
 157                                 sortByProperty( modules, 'size', true );
 158
 159                                 // Convert size to human-readable string.
 160                                 $.each( modules, function ( i, module ) {
 161                                         module.size = module.size > 1024 ?
 162                                                 ( module.size / 1024 ).toFixed( 2 ) + ' KB' :
 163                                                 ( module.size !== null ? module.size + ' B' : null );
 164                                 } );
 165
 166                                 return modules;
 167                         },
 168
 169                         /**
 170                          * For each module with styles, count the number of selectors, and
 171                          * count how many match against some element currently in the DOM.
 172                          */
 173                         css: function () {
 174                                 var modules = [];
 175
 176                                 $.each( inspect.getLoadedModules(), function ( index, name ) {
 177                                         var css, stats, module = mw.loader.moduleRegistry[name];
 178
 179                                         try {
 180                                                 css = module.style.css.join();
 181                                         } catch (e) { return; } // skip
 182
 183                                         stats = inspect.auditSelectors( css );
 184                                         modules.push( {
 185                                                 module: name,
 186                                                 allSelectors: stats.total,
 187                                                 matchedSelectors: stats.matched,
 188                                                 percentMatched: stats.total !== 0 ?
 189                                                         ( stats.matched / stats.total * 100 ).toFixed( 2 )  + '%' : null
 190                                         } );
 191                                 } );
 192                                 sortByProperty( modules, 'allSelectors', true );
 193                                 return modules;
 194                         },
 195                 }
 196         };
 197
 198         if ( mw.config.get( 'debug' ) ) {
 199                 mw.log( 'mw.inspect: reports are not available in debug mode.' );
 200         }
 201
 202         mw.inspect = inspect;
 203
 204 }( mediaWiki, jQuery ) );