file.js

var _marked = [createIterator].map(regeneratorRuntime.mark);

var array = [1, 2, 3];

function createIterator(arr) {
    var _iteratorNormalCompletion, _didIteratorError, _iteratorError, _iterator, _step, item;

    return regeneratorRuntime.wrap(function createIterator$(_context) {
        while (1) {
            switch (_context.prev = _context.next) {
                case 0:
                    _iteratorNormalCompletion = true;
                    _didIteratorError = false;
                    _iteratorError = undefined;
                    _context.prev = 3;
                    _iterator = arr[Symbol.iterator]();

                case 5:
                    if (_iteratorNormalCompletion = (_step = _iterator.next()).done) {
                        _context.next = 12;
                        break;
                    }

                    item = _step.value;
                    _context.next = 9;
                    return item;

                case 9:
                    _iteratorNormalCompletion = true;
                    _context.next = 5;
                    break;

                case 12:
                    _context.next = 18;
                    break;

                case 14:
                    _context.prev = 14;
                    _context.t0 = _context["catch"](3);
                    _didIteratorError = true;
                    _iteratorError = _context.t0;

                case 18:
                    _context.prev = 18;
                    _context.prev = 19;

                    if (!_iteratorNormalCompletion && _iterator.return) {
                        _iterator.return();
                    }

                case 21:
                    _context.prev = 21;

                    if (!_didIteratorError) {
                        _context.next = 24;
                        break;
                    }

                    throw _iteratorError;

                case 24:
                    return _context.finish(21);

                case 25:
                    return _context.finish(18);

                case 26:
                case "end":
                    return _context.stop();
            }
        }
    }, _marked[0], this, [[3, 14, 18, 26], [19,, 21, 25]]);
}

var reference = createIterator(array);

console.log(reference.next()); // { value: 1, done: false }
console.log(reference.next()); // { value: 2, done: false }
console.log(reference.next()); // { value: 3, done: false }
console.log(reference.next()); // { value: undefined, done: true }