| // Copyright (c) 2016, the Dart project authors. Please see the AUTHORS file |
| // for details. All rights reserved. Use of this source code is governed by a |
| // BSD-style license that can be found in the LICENSE file. |
| |
| // @dart = 2.9 |
| |
| /// @assertion Future doWhile(FutureOr<bool> f()) |
| /// Performs an async operation repeatedly until it returns false. |
| /// The function f is called repeatedly while it returns either the bool |
| /// value true or a Future which completes with the value true. |
| /// If a call to f returns false or a Future that completes to false, |
| /// iteration ends and the future returned by doWhile is completed. |
| /// |
| /// @description Checks that [f] may return a Future that completes to a bool. |
| /// @author ngl@unipro.ru |
| |
| import "dart:async"; |
| import "../../../Utils/expect.dart"; |
| |
| const int N = 5; |
| |
| main() { |
| int num = 0; |
| |
| FutureOr<bool> f() { |
| num++; |
| return new Future.value(num < N); |
| } |
| |
| asyncStart(); |
| Future.doWhile(f).then( |
| (_) { |
| Expect.equals(N, num); |
| asyncEnd(); |
| } |
| ); |
| } |