如何从RxJs中的flatMap返回其他值 [英] How to return additional values from flatMap in RxJs

问题描述

在以下设置中，我需要从flatMap返回除Observable，key字符串以外的其他值:

I need to return an additional value other than Observable, key string from flatMap from below setup:

this.subscribeInit = this.tradingService.getInProgress()
.pipe(flatMap((s) => {
    this.keys = s.map((tdi) => tdi.key);
    return this.keys;
}),
flatMap((key) =>{
    var res = this.tradingService.getTradingData(key);//returns `Observable<any>`
    return res;
}))
.subscribe(res => {
    console.log('Key is : ' + res.key);
}, 
undefined,
() => this.onComplete());

类似的东西:

flatMap((key) =>{
    var res = this.tradingService.getTradingData(key);
    return {res,key};
}))

如何实现?

推荐答案

只需使用地图...

flatMap((key) =>{
    return this.tradingService.getTradingData(key).pipe(map((res) => {
        return {res,key};
    }));
}))

ps:我有点困惑:不推荐使用flatMap并替换我的mergeMap，switchMap，...吗?

ps: i am a bit confused: isnt flatMap deprecated and replaced my mergeMap, switchMap, ... ?

显然，问题是由使用flatMap而不是mergeMap引起的.

edit: apparently the problem was caused by using flatMap instead of mergeMap.

这篇关于如何从RxJs中的flatMap返回其他值的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！