try {
if (typeof Iterator !== 'function') throw new Error('Iterator missing');
if (typeof Iterator.from !== 'function') throw new Error('Iterator.from missing');
var iter = Iterator.from([1, 2, 3]);
if (typeof iter.map !== 'function') throw new Error('Iterator.prototype.map missing');
if (typeof iter.filter !== 'function') throw new Error('Iterator.prototype.filter missing');
if (typeof iter.take !== 'function') throw new Error('Iterator.prototype.take missing');
console.log('OK');
} catch (e) {
console.log('NO:', e.message);
}