Function AsyncIterator

docs/app/js/sanddance-app.js:53252–53278

(generator, PromiseImpl)

        });
    }
    function AsyncIterator(generator, PromiseImpl) {
        function invoke(method, arg, resolve, reject) {
            var record = tryCatch(generator[method], generator, arg);
            if ("throw" !== record.type) {
                var result = record.arg, value1 = result.value;
                return value1 && "object" == _typeof(value1) && hasOwn.call(value1, "__await") ? PromiseImpl.resolve(value1.__await).then(function(value) {
                    invoke("next", value, resolve, reject);
                }, function(err) {
                    invoke("throw", err, resolve, reject);
                }) : PromiseImpl.resolve(value1).then(function(unwrapped) {
                    result.value = unwrapped, resolve(result);
                }, function(error) {
                    return invoke("throw", error, resolve, reject);
                });
            }
            reject(record.arg);
        }
        var previousPromise;
        this._invoke = function(method, arg) {
            function callInvokeWithMethodAndArg() {
                return new PromiseImpl(function(resolve, reject) {
                    invoke(method, arg, resolve, reject);
                });
            }
            return previousPromise = previousPromise ? previousPromise.then(callInvokeWithMethodAndArg, callInvokeWithMethodAndArg) : callInvokeWithMethodAndArg();
        };
    }
    function maybeInvokeDelegate(delegate, context) {
        var method = delegate.iterator[context.method];
        if (undefined === method) {