is-implemented.js 401 Bytes
'use strict';

module.exports = function () {
	var arr = [1, 'foo'], iterator, result;
	if (typeof arr.keys !== 'function') return false;
	iterator = arr.keys();
	if (!iterator) return false;
	if (typeof iterator.next !== 'function') return false;
	result = iterator.next();
	if (!result) return false;
	if (result.value !== 0) return false;
	if (result.done !== false) return false;
	return true;
};