javascript - 如何让一个 Observable 序列在发射之前等待另一个序列完成？

Question

假设我有一个Observable，像这样:

var one = someObservable.take(1);

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

然后，我有第二个Observable:

var two = someOtherObservable.take(1);

现在，我想subscribe()到two，但我想确保one在之前完成两个订阅者被解雇。

我可以在two上使用什么样的缓冲方法让第二个等待第一个完成？

我想我要暂停 two 直到 one 完成。

Answer 1

我能想到的几种方法

import {take, publish} from 'rxjs/operators'
import {concat} from 'rxjs'

//Method one

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

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