console.time.js

/**
 * polyfilling console.time & timeEnd 
 * on IE
 */

(function( console ) {

  // cache to hold running timers
  console._timers = {};

  /**
   * start timer
   * 
   * @param {string} key  timer name
   */
   
  console.time = function( key ) {
    console._timers[ key ] = new Date().getTime();
  }

  /**
   * end timer
   * 
   * @param {string} key
   */
   
  console.timeEnd = function( key ) {
    var current = new Date().getTime();
    var started = console._timers[ key ];

    console.info( '{key}: {duration}ms'.replace( /{key}/, key ).replace( /{duration}/, current - started ) );

    // release timer
    delete console._timers[ key ];
  }

})( this.console = this.console || {} );