'use strict';

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

module.exports = function shimContains() {
	var polyfill = getPolyfill();
	if (typeof document !== 'undefined') {
		define(
			document,
			{ contains: polyfill },
			{ contains: function () { return document.contains !== polyfill; } }
		);
		if (typeof Element !== 'undefined') {
			define(
				Element.prototype,
				{ contains: polyfill },
				{ contains: function () { return Element.prototype.contains !== polyfill; } }
			);
		}
	}
	return polyfill;
};