javascript - 将 observables 的 observables 数组转换为 observables rxjs 数组

Question

为了简化问题，我在这里使用了数字和字符串。代码:

const numbers$:Observable<number[]> = of([1,2,3]);
const strings: string[] = ["a","b"];

function getStrings(): Observable<string>[]{
   return numbers$.pipe( 
     map((numbers: number[]) => {
       const strings$: Observable<string>[] =  strings.map(s => of(s));
       return strings$;
     }),
  )
}

getStrings().subscribe(x => console.log(x))

我收到的错误是: Type 'Observable<Observable<string>[]>' is missing the following properties from type 'Observable<string>[]我怎样才能得到Observable<string>[]来自getStrings功能？我尝试过使用 flatMap、switchMap 但无法得到完美的组合。

Stackblitz

Answer 1

您需要使用 mergeMap() 和 forkJoin():

function getStrings(): Observable<string[]>{
   return numbers$.pipe( 
     mergeMap((numbers: number[]) => {
       const strings$: Observable<string>[] =  strings.map(s => of(s));
       return forkJoin(strings$);
     }),
  )
}

getStrings().subscribe(x => console.log(x))

https://stackblitz.com/edit/rxjs-dzvsbh?file=index.ts