对于未完成的可观察变量的forkJoin替代方案?

问题描述

constructor(
    private route: ActivatedRoute,
    private http: Http
){
    // Observe parameter changes
    let paramObs = route.paramMap;

    // Fetch data once
    let dataObs = http.get('...');

    // Subscribe to both observables,
    // use both resolved values at the same level
}

是否存在与forkJoin类似的东西，每当发出参数更改时都会触发? forkJoin仅在所有可观察物都完成后才能起作用.

Is there something similar to forkJoin that triggers whenever a parameter change is emitted? forkJoin only works when all observables have completed.

我只需要避免回调地狱，欢迎任何符合要求的选择.

I just need to avoid callback hell, any alternative that complies is welcome.

推荐答案

有几种选择:

1. 结合使用take(1)和forkJoin()来完成每个可观察到的源:

1. Use take(1) with forkJoin() to complete each source Observable:

forkJoin(o1$.take(1), o2$.take(1))

使用 zip() 和take(1)仅在所有源可观察对象发出相同数量的项目时发出:

Use zip() and take(1) to emit only when all source Observables have emitted the same number of items:

zip(o1$, o2$).take(1)

使用 combineLatest() 在任何源Observable发出时发出:

Use combineLatest() to emit when any of the source Observables emit:

combineLatest(o1$, o2$)

2019年1月:已针对RxJS 6更新

Jan 2019: Updated for RxJS 6

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