如何在发射之前使一个RxJS Observable序列等待另一个RxJS Observable序列完成？ [英] How can I make one RxJS Observable sequence wait for another to complete before emitting?

问题描述

说我有一个Observable，如下所示：

Say I have an Observable, like so:

var one = someObservable.take(1);

one.subscribe(function(){ /* do something */ });

然后，我有第二个可观察量：

Then, I have a second observable:

var two = someOtherObservable.take(1);

现在，我想订阅两个 ，但我想在两个订阅者被解雇之前确保一个已完成。我可以在两个上使用什么样的缓冲方法让第二个等待第一个完成？

Now, I want to subscribe to two, but I want to make sure that one has completed before the two subscriber is fired. What kind of buffering method can I use on two to make the second one wait for the first one to be completed?

我想我想暂停两个，直到一个完成。

I suppose I am looking to pause two until one is complete.

推荐答案

我能想到的几种方式

//Method one
var one = someObservable.take(1);
var two = someOtherObservable.take(1);
one.concat(two).subscribe(function() {/*do something */});

//Method two, if they need to be separate for some reason
var one = someObservable.take(1);
var two = someOtherObservable.take(1).publish();
two.subscribe(function(){/*do something */});
one.subscribe(function(){/*do something */}, null, two.connect.bind(two));

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