array.prototype.unshift/shim.js

ES spec-compliant `Array.prototype.unshift` shim/polyfill/replacement that works as far down as ES3.

'use strict';

var define = require('define-properties');
var getPolyfill = require('./polyfill');

module.exports = function shimArrayPrototypeUnshift() {
	var polyfill = getPolyfill();

	define(
		Array.prototype,
		{ unshift: polyfill },
		{ unshift: function () { return Array.prototype.unshift !== polyfill; } }
	);

	return polyfill;
};