angular.js/src/service/log.js

'use strict';

/**
 * @ngdoc service
 * @name angular.service.$log
 * @requires $window
 *
 * @description
 * Simple service for logging. Default implementation writes the message
 * into the browser's console (if present).
 *
 * The main purpose of this service is to simplify debugging and troubleshooting.
 *
 * @example
    <doc:example>
      <doc:source>
         <script>
           function LogCtrl($log) {
             this.$log = $log;
             this.message = 'Hello World!';
           }
         </script>
         <div ng:controller="LogCtrl">
           <p>Reload this page with open console, enter text and hit the log button...</p>
           Message:
           <input type="text" ng:model="message"/>
           <button ng:click="$log.log(message)">log</button>
           <button ng:click="$log.warn(message)">warn</button>
           <button ng:click="$log.info(message)">info</button>
           <button ng:click="$log.error(message)">error</button>
         </div>
      </doc:source>
      <doc:scenario>
      </doc:scenario>
    </doc:example>
 */
var $logFactory; //reference to be used only in tests
angularServiceInject("$log", $logFactory = function($window){
  return {
    /**
     * @ngdoc method
     * @name angular.service.$log#log
     * @methodOf angular.service.$log
     *
     * @description
     * Write a log message
     */
    log: consoleLog('log'),

    /**
     * @ngdoc method
     * @name angular.service.$log#warn
     * @methodOf angular.service.$log
     *
     * @description
     * Write a warning message
     */
    warn: consoleLog('warn'),

    /**
     * @ngdoc method
     * @name angular.service.$log#info
     * @methodOf angular.service.$log
     *
     * @description
     * Write an information message
     */
    info: consoleLog('info'),

    /**
     * @ngdoc method
     * @name angular.service.$log#error
     * @methodOf angular.service.$log
     *
     * @description
     * Write an error message
     */
    error: consoleLog('error')
  };

  function consoleLog(type) {
    var console = $window.console || {};
    var logFn = console[type] || console.log || noop;
    if (logFn.apply) {
      return function() {
        var args = [];
        forEach(arguments, function(arg){
          args.push(formatError(arg));
        });
        return logFn.apply(console, args);
      };
    } else {
      // we are IE, in which case there is nothing we can do
      return logFn;
    }
  }
}, ['$window']);