如何在rxjs中执行链序列

本文介绍了如何在rxjs中执行链序列的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我想要这样的事情：

this._myService.doSomething().subscribe(result => {
  doSomething()
});
.then( () => dosthelse() )
.then( () => dosanotherthing() )

所以我想像承诺一样链接.then。我如何在Rxjs中做到这一点？

So I would like to chain .then like in promise. How would I do that in Rxjs?

this._myService.getLoginScreen().subscribe( result => {
      window.location.href = MyService.LOGIN_URL;
      /// I would like to wait for the site to load and alert something from       the url, when I do it here it alerts the old one
    });
   .then (alert(anotherService.partOfTheUrl())


getLoginScreen() {
  return this.http.get(myService.LOGIN_URL)
.flatMap(result => this.changeBrowserUrl())
.subscribe( result => //i want to do sth when the page is loaded//);
}

changeBrowserUrl(): Observable<any> {
return Observable.create( observer => {
window.location.href = myService.LOGIN_URL;
observer.next();
});
}

推荐答案

对于observable，相当于然后将是 flatMap 。您可以在这里看到一些使用示例：

The equivalent of then for observables would be flatMap. You can see some examples of use here :

RxJS Promise Composition (passing data)
Why we need to use flatMap?
RxJS sequence equvalent to promise.then()?

对于您的示例，您可以执行以下操作：

For your example, you could do something like :

this._myService.doSomething()
  .flatMap(function(x){return functionReturningObservableOrPromise(x)})
  .flatMap(...ad infinitum)
  .subscribe(...final processing)

注意函数返回的类型，以及使用 flatMap 的链可观察量你将需要返回一个promise或一个observable。

Pay attention to the types of what your functions return, as to chain observables with flatMap you will need to return a promise or an observable.

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Observables