Rxjs - remap object with observables as values

Question

I got an observable like this:

  const original = Observable.of({
    a: this.http.get('https://jsonplaceholder.typicode.com/todos/11'),
    b: this.http.get('https://jsonplaceholder.typicode.com/todos/22'),
    c: this.http.get('https://jsonplaceholder.typicode.com/todos/33')
  });

I need to resolve the inner observables and get something like this in the subscribe handler:

  {
    a: ResponseFromServer,
    b: ResponseFromServer,
    c: ResponseFromServer,
  }

How should I approach this problem?

Thanks.

EDIT: I've figured it out, read below.

It seems that not many people know that *Map operators used to have something called resultSelector as their second argument. Now in rxjs v6, you can do the same with inner map, let me show you.

const original = Observable.of({
    a: this.http.get('https://jsonplaceholder.typicode.com/todos/11'),
    b: this.http.get('https://jsonplaceholder.typicode.com/todos/22'),
    c: this.http.get('https://jsonplaceholder.typicode.com/todos/33')
});

const transformed = original.pipe(
    mergeMap(sourceValue => 
        forkJoin(_.values(sourceValue)).pipe(map(resolvedHttpRequests => {
            // here you have access to sourceValue as well as resolvedHttpRequests so you can do manual join to match the data.
        }))
    )
)

Answer 1

Update for 2020

forkJoin(
  // as of RxJS 6.5+ we can use a dictionary of sources
  {
    google: ajax.getJSON('https://api.github.com/users/google'),
    microsoft: ajax.getJSON('https://api.github.com/users/microsoft'),
    users: ajax.getJSON('https://api.github.com/users')
  }
)
  // { google: object, microsoft: object, users: array }
  .subscribe(console.log);

https://www.learnrxjs.io/learn-rxjs/operators/combination/forkjoin