1 // https://github.com/tc39/proposal-iterator-helpers
2 var $ = require('../internals/export');
3 var apply = require('../internals/function-apply');
4 var anObject = require('../internals/an-object');
5 var toObject = require('../internals/to-object');
6 var isPrototypeOf = require('../internals/object-is-prototype-of');
7 var IteratorPrototype = require('../internals/iterators-core').IteratorPrototype;
8 var createIteratorProxy = require('../internals/iterator-create-proxy');
9 var getIterator = require('../internals/get-iterator');
10 var getIteratorMethod = require('../internals/get-iterator-method');
12 var IteratorProxy = createIteratorProxy(function (args) {
13 var result = anObject(apply(this.next, this.iterator, args));
14 var done = this.done = !!result.done;
15 if (!done) return result.value;
18 $({ target: 'Iterator', stat: true }, {
19 from: function from(O) {
20 var object = toObject(O);
21 var usingIterator = getIteratorMethod(object);
24 iterator = getIterator(object, usingIterator);
25 if (isPrototypeOf(IteratorPrototype, iterator)) return iterator;
28 } return new IteratorProxy({ iterator: iterator });