| /* |
| * Copyright (c) 2011, 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. |
| */ |
| /** |
| * @assertion Future<T> firstWhere (bool test(T element), { |
| * @deprecated dynamic defaultValue(), T orElse()}) |
| * |
| * Finds the first element of this stream matching test. |
| * |
| * Returns a future that is completed with the first element of this stream that |
| * test returns true for. |
| * |
| * If no such element is found before this stream is done, and a orElse function |
| * is provided, the result of calling orElse becomes the value of the future. If |
| * orElse throws, the returned future is completed with that error. |
| * |
| * If this stream emits an error before the first matching element, the returned |
| * future is completed with that error, and processing stops. |
| * |
| * Stops listening to the stream after the first matching element or error has |
| * been received. |
| * |
| * Internally the method cancels its subscription after the first element that |
| * matches the predicate. This means that single-subscription (non-broadcast) |
| * streams are closed and cannot be reused after a call to this method. |
| * |
| * If an error occurs, or if this stream ends without finding a match and with |
| * no orElse function provided, the returned future is completed with an error. |
| * |
| * The defaultValue parameter is deprecated, and orElse should be used instead. |
| * @description Checks that if element is found, it is passed to the resulting |
| * future. |
| * @author kaigorodov |
| */ |
| import "dart:async"; |
| import "../../../Utils/expect.dart"; |
| import "IsolateStream.dart" as IsolateStream; |
| |
| void check1(Iterable data, bool test(var element), var expected) { |
| Stream s = IsolateStream.fromIterable(data); |
| asyncStart(); |
| Future f = s.firstWhere(test); |
| f.then((actual) { |
| Expect.equals(expected, actual); |
| asyncEnd(); |
| }); |
| } |
| |
| void check2(Iterable data, bool test(var element), var expected) { |
| Stream s = new Stream.fromIterable(data); |
| asyncStart(); |
| Future f = s.firstWhere(test, orElse: () { |
| Expect.fail("should not be called"); |
| }); |
| f.then((actual) { |
| Expect.equals(expected, actual); |
| asyncEnd(); |
| }); |
| } |
| |
| void check(Iterable data, bool test(var element), var expected) { |
| check1(data, test, expected); |
| check2(data, test, expected); |
| } |
| |
| main() { |
| check([1, 2, 3], (var element) => true, 1); |
| check([1, 2, 3], (var element) => element != null, 1); |
| check([1, 2, 3, null], (var element) => element == null, null); |
| check([1, 2, 3], (var element) => element > 2, 3); |
| check(new Iterable.generate(10, (int index) => index * 5), |
| (var element) => element != 30, 0); |
| check(new Iterable.generate(10, (int index) => index * 5), |
| (var element) => element == 30, 30); |
| } |