Array.prototype.filter = function(fun/*, thisArg*/) {
	'use strict';

	if (this === void 0 || this === null) {
		throw new TypeError();
	}

	var t = Object(this);
	var len = t.length >>> 0;
	if (typeof fun !== 'function') {
		throw new TypeError();
	}

	var res = [];
	var thisArg = arguments.length >= 2 ? arguments[1] : void 0;
	for (var i = 0; i < len; i++) {
		if (i in t) {
			var val = t[i];

			// NOTE: Technically this should Object.defineProperty at
			//       the next index, as push can be affected by
			//       properties on Object.prototype and Array.prototype.
			//       But that method's new, and collisions should be
			//       rare, so use the more-compatible alternative.
			if (fun.call(thisArg, val, i, t)) {
				res.push(val);
			}
		}
	}

	return res;
};