resources/src/mediawiki/mediawiki.errorLogger.js

   1 /**
   2  * Try to catch errors in modules which don't do their own error handling.
   3  * @class mw.errorLogger
   4  * @singleton
   5  */
   6 ( function ( mw ) {
   7         'use strict';
   8
   9         mw.errorLogger = {
  10                 /**
  11                  * Fired via mw.track when an error is not handled by local code and is caught by the
  12                  * window.onerror handler.
  13                  *
  14                  * @event global_error
  15                  * @param {string} errorMessage Error errorMessage.
  16                  * @param {string} url URL where error was raised.
  17                  * @param {number} lineNumber Line number where error was raised.
  18                  * @param {number} [columnNumber] Line number where error was raised. Not all browsers
  19                  *   support this.
  20                  * @param {Error|Mixed} [errorObject] The error object. Typically an instance of Error, but anything
  21                  *   (even a primitive value) passed to a throw clause will end up here.
  22                  */
  23
  24                 /**
  25                  * Install a window.onerror handler that will report via mw.track, while preserving
  26                  * any previous handler.
  27                  * @param {Object} window
  28                  */
  29                 installGlobalHandler: function ( window ) {
  30                         // We will preserve the return value of the previous handler. window.onerror works the
  31                         // opposite way than normal event handlers (returning true will prevent the default
  32                         // action, returning false will let the browser handle the error normally, by e.g.
  33                         // logging to the console), so our fallback old handler needs to return false.
  34                         var oldHandler = window.onerror || function () { return false; };
  35
  36                         /**
  37                          * Dumb window.onerror handler which forwards the errors via mw.track.
  38                          * @fires global_error
  39                          */
  40                         window.onerror = function ( errorMessage, url, lineNumber, columnNumber, errorObject ) {
  41                                 mw.track( 'global.error', { errorMessage: errorMessage, url: url,
  42                                         lineNumber: lineNumber, columnNumber: columnNumber, errorObject: errorObject } );
  43                                 return oldHandler.apply( this, arguments );
  44                         };
  45                 }
  46         };
  47
  48         mw.errorLogger.installGlobalHandler( window );
  49 }( mediaWiki ) );