Array.prototype.includes = function(searchElement /*, fromIndex*/) {
	'use strict';
	if (this == null) {
		throw new TypeError('Array.prototype.includes called on null or undefined');
	}

	var O = Object(this);
	var len = parseInt(O.length, 10) || 0;
	if (len === 0) {
		return false;
	}
	var n = parseInt(arguments[1], 10) || 0;
	var k;
	if (n >= 0) {
		k = n;
	} else {
		k = len + n;
		if (k < 0) {k = 0;}
	}
	var currentElement;
	while (k < len) {
		currentElement = O[k];
		if (searchElement === currentElement ||
			(searchElement !== searchElement && currentElement !== currentElement)) { // NaN !== NaN
			return true;
		}
		k++;
	}
	return false;
};