'use strict';

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

/* http://www.ecma-international.org/ecma-262/6.0/#sec-number.isnan */

module.exports = function shimNumberIsNaN() {
	var polyfill = getPolyfill();
	define(Number, { isNaN: polyfill }, {
		isNaN: function testIsNaN() {
			return Number.isNaN !== polyfill;
		}
	});
	return polyfill;
};