The TakeWhile mirrors the source Observable until such time as some condition you specify becomes false, at which point TakeWhile stops mirroring the source Observable and terminates its own Observable.
待定
The takeWhile operator returns an Observable that mirrors the behavior of the source Observable until such time as a function, applied to an item emitted by that Observable, returns false, whereupon the new Observable terminates with an onCompleted notification.
响应式扩展numbers = Observable.from( [1, 2, 3, 4, 5, 6, 7, 8, 9] );
numbers.takeWhile({ ((it < 6) || (0 == (it % 2))) }).subscribe(
{ println(it); }, // onNext
{ println("Error: " + it.getMessage()); }, // onError
{ println("Sequence complete"); } // onCompleted
);1 2 3 4 5 6 Sequence complete
takeWhile does not by default operate on any particular Scheduler.
takeWhile(Func1)
The takeWhile operator returns an Observable that mirrors the behavior of the source Observable until such time as a function, applied to an item emitted by that Observable, returns false, whereupon the new Observable terminates with an onCompleted notification.
takeWhile does not by default operate on any particular Scheduler.
takeWhile(Func1)
RxJS 实现 takeWhile 运算符。你可以向它传递一个函数来控制获取过程。takeWhile 会对源可观察对象发出的每个项目调用该函数，直到该函数返回 false 为止，此时 takeWhile 会停止镜像源可观察对象（从该项目开始）并发出 onCompleted 通知。该函数接受三个参数
您可以选择向 takeWhile 传递第二个参数。如果是这样，该项目也会作为“this”提供给你的谓词函数。
var source = Rx.Observable.range(1, 5)
.takeWhile(function (x) { return x < 3; });
var subscription = source.subscribe(
function (x) { console.log('Next: ' + x); },
function (err) { console.log('Error: ' + err); },
function () { console.log('Completed'); });Next: 0 Next: 1 Next: 2 Completed
takeWhile 存在于以下每个发行版中
rx.jsrx.all.jsrx.all.compat.jsrx.compat.jsrx.lite.jsrx.lite.compat.jsRxPHP 将此运算符实现为 takeWhile。
只要指定条件为真，就返回来自可观察序列的元素。它接受一个回调作为参数，用于测试每个源元素的条件。回调谓词使用元素的值进行调用。
//from https://github.com/ReactiveX/RxPHP/blob/master/demo/take/takeWhile.php
$source = \Rx\Observable::range(1, 5)
->takeWhile(function ($x) {
return $x < 3;
});
$subscription = $source->subscribe($stdoutObserver);
Next value: 1
Next value: 2
Complete!
RxPHP 还具有一个运算符 takeWhileWithIndex。
只要指定条件为真，就返回来自可观察序列的元素。它接受一个回调作为参数，用于测试每个源元素的条件。回调谓词使用索引和元素的值进行调用。
//from https://github.com/ReactiveX/RxPHP/blob/master/demo/take/takeWhileWithIndex.php
$source = \Rx\Observable::range(1, 5)
->takeWhileWithIndex(function ($i) {
return $i < 3;
});
$subscription = $source->subscribe($stdoutObserver);
Next value: 1
Next value: 2
Next value: 3
Complete!