如何解决在 Rxjs 中发送到 Subject 参数的 promise？

Question

I pass a Promise to Subject as parameter:

const work = new Subject<{ id: number; dialogRef: Promise<typeof Dialog> }>();

And I want to use the instance inside the promise later:

...
exhaustMap(({ id, dialogRef }) =>
  http.get({ id }).pipe(tap(() => dialogRef.close()))
)
...

But the problem is dialogRef is a Promise , I need to resolve it before I use instance function ( close() ).

The one way I was be able to do that is using async await , but this solution is not good for me. because I want to do it using "rxjs" way.

I looking for operator or function that can resolve this promise and pass it to exhaustMap operator. something like that:

 resolve(({ dialogRef }) => dialogRef),
 exhaustMap(({ id, dialogRef }) => //<-- dialogRef is NOT promise. it's instance
      http.get({ id }).pipe(tap(() => dialogRef.close()))
 )

Can I do it with rxjs?

stackblitz

import { of, Subject } from 'rxjs';
import { exhaustMap, tap } from 'rxjs/operators';
console.clear();

const http = {
  get: ({ id }) => of(`data: ${id}`),
};

const Dialog = {
  close: () => {
    console.log('in close!');
  },
};

const work = new Subject<{ id: number; dialogRef: Promise<typeof Dialog> }>();

work
  .pipe(
    exhaustMap(({ id, dialogRef }) =>
      http.get({ id }).pipe(tap(async () => (await dialogRef).close()))
    )
  )
  .subscribe((r) => {
    console.log({ r });
  });

work.next({ id: 1, dialogRef: Promise.resolve(Dialog) });

Answer 1

like this? https://stackblitz.com/edit/rxjs-geomjb

work.pipe(
    concatMap(({ id, dialogRef }) => forkJoin({ id: of(id), dialogRef })),
    exhaustMap(({ id, dialogRef }) => http.get({ id }).pipe(tap(() => dialogRef.close())))
).subscribe(...);

Answer 2

use concat like this:

work.pipe(
  exhaustMap(({id, dialogRef}) => concat(http.get(id), dialogRef.close()))
).subscribe()

If you want to run dialogRef.close after http.get , just add defer for it:

work.pipe(
  exhaustMap(({id, dialogRef}) => concat(
    http.get(id),
    defer(() => dialogRef.close())
  ))
).subscribe()