| // https://github.com/tc39/proposal-iterator-helpers |
| var $ = require('../internals/export'); |
| var path = require('../internals/path'); |
| var aFunction = require('../internals/a-function'); |
| var anObject = require('../internals/an-object'); |
| var toObject = require('../internals/to-object'); |
| var createIteratorProxy = require('../internals/create-iterator-proxy'); |
| var getIteratorMethod = require('../internals/get-iterator-method'); |
| |
| var Iterator = path.Iterator; |
| |
| var IteratorProxy = createIteratorProxy(function (arg) { |
| var result = anObject(this.next.call(this.iterator, arg)); |
| var done = this.done = !!result.done; |
| if (!done) return result.value; |
| }, true); |
| |
| $({ target: 'Iterator', stat: true }, { |
| from: function from(O) { |
| var object = toObject(O); |
| var usingIterator = getIteratorMethod(object); |
| var iterator; |
| if (usingIterator != null) { |
| iterator = aFunction(usingIterator).call(object); |
| if (iterator instanceof Iterator) return iterator; |
| } else { |
| iterator = object; |
| } return new IteratorProxy({ |
| iterator: iterator |
| }); |
| } |
| }); |