Question

是否有一种方法在订阅了一个可观察对象之后再添加一个元素？

observable = timer(1000,2000).take(5)
observable.subscribe()
//Now I want to add one more element to observable....

Answer 1

也许您正在寻找一个主题，一个主题既可以观察又可以观察。

const { Subject, timer, fromEvent } = rxjs;
const { take } = rxjs.operators;

let subject$ = new Subject();

subject$.subscribe(val =>  { console.log(val); });

timer(1000,2000).pipe(take(5)).subscribe(val => { subject$.next(val); });

fromEvent(document.getElementsByTagName('button')[0], 'click').subscribe(() => {
  subject$.next('clicked');
});

<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/6.5.3/rxjs.umd.min.js"></script>
<button>Click</button>

Answer 2

您可以结合使用merge和Subjects

const { Subject, timer, merge } = rxjs;
const { take } = rxjs.operators;

let source_1 = timer(1000,2000).pipe(take(5));
let source_2 = new Subject();

let final_source = merge(
  source_1,
  source_2
);

final_source.subscribe(e => console.log(e));

source_2.next('jabadabadoo!');

<script src="https://cdnjs.cloudflare.com/ajax/libs/rxjs/6.5.3/rxjs.umd.min.js"></script>

RxJS订阅后添加一个可观察的对象

2 个答案: