fabric.js/src/util/lang_function.js

/* _ES5_COMPAT_START_ */
(function() {

  var slice = Array.prototype.slice,
      apply = Function.prototype.apply,
      Dummy = function() { };

  if (!Function.prototype.bind) {
    /**
     * Cross-browser approximation of ES5 Function.prototype.bind (not fully spec conforming)
     * @see <a href="https://developer.mozilla.org/en/JavaScript/Reference/Global_Objects/Function/bind">Function#bind on MDN</a>
     * @param {Object} thisArg Object to bind function to
     * @param {Any[]} Values to pass to a bound function
     * @return {Function}
     */
    Function.prototype.bind = function(thisArg) {
      var _this = this, args = slice.call(arguments, 1), bound;
      if (args.length) {
        bound = function() {
          return apply.call(_this, this instanceof Dummy ? this : thisArg, args.concat(slice.call(arguments)));
        };
      }
      else {
        /** @ignore */
        bound = function() {
          return apply.call(_this, this instanceof Dummy ? this : thisArg, arguments);
        };
      }
      Dummy.prototype = this.prototype;
      bound.prototype = new Dummy();

      return bound;
    };
  }

})();
/* _ES5_COMPAT_END_ */