Support dictionary in combineLatest

[Akxe]

Feature Request

combineLatest should accept dictionary/object same as forkJoin. Implementation in forkJoin #4640

combineLatest({
  width: this.width$,
  height: this.height$,
}).pipe(
  tap(({width, height}) => console.log(`dimensions: ${width}x${height}`))
)

Reasoning

It is much easier to mess up when deconstructing array than deconstructiong object. Thus this change would enable developer to name their streams, reducing the potential for error.

[benlesh]

This is something we're planning, but I'm not sure we can do until the deprecated versions of combineLatest are removed in version 8.

[intellix]

This would be awesome in Angular. When transitioning to observable values the view can get real messy and pyramid like:

<ng-container *ngIf="(a$ | async) as a">
  <ng-container *ngIf="(b$ | async) as b">
    <ng-container *ngIf="(c$ | async) as c">
      {{ a }} {{ b }} {{ c }}
      {{ a }} {{ b }} {{ c }}
    </ng-container>
  </ng-container>  
</ng-container>

Would be nice to just use a single async pipe at the top and use values like they're not async. Ofc it's not to do with any frontend framework but it's one of the things that makes me groan about refactoring to use Rx

<ng-container *ngIf="(abc$ | async) as abc">
  {{ abc.a }} {{ abc.b }} {{ abc.c }}
  {{ abc.a }} {{ abc.b }} {{ abc.c }}
</ng-container>

[amakhrov]

Currently a workaround is to use array-based combineLatest followed by map():

const abc$ = combineLatest([a$, b$, c$]).pipe(
  map(([a, b, c]) => ({a, b, c}))
)

It's not too bad, but it results it repeating code (also error-prone, as @Akxe has pointed out)

Also it's probably not too hard to create a custom wrapper to implement that in your project.

[rraziel]

Is there any plan on implementing this, or at least would a pull request be considered for merging?

[Goobles]

You can create your own operator function as a workaround:
https://gist.github.com/Goobles/45f0b3027d31884dba0b164ee2cc50ea

[Akxe]

@rraziel I belive this can now be closed, right?

[rraziel]

@Akxe this is available in rxjs 7 yes

[tmtron]

RxJs7 docs: Combine a dictionary of Observables