Angular2 Observable - Await multiple function calls before proceeding

I have been doing this with forkJoin

import {Observable} from 'rxjs/Observable';
import 'rxjs/add/observable/forkJoin';

Observable.forkJoin(
  this.http.get('./friends.json').map((res: Response) => res.json()),
  this.http.get('./customer.json').map((res: Response) => res.json())
)
.subscribe(res => this.combined = {friends: res[0].friends, customer: res[1]});

Some more info here: http://www.syntaxsuccess.com/viewarticle/angular-2.0-and-http

In RxJS v6 and later you can do this more eloquently with zip.

    import { zip } from 'rxjs';

    const promise1 = yourSvc.get(yourFavoriteAPI.endpoint1);
    const promise2 = yourSvc.get(yourFavoriteAPI.endpoint2);

    const promises = zip(promise1, promise2);

    promises.subscribe(([data1, data2]) => {
      console.log(data1);
      console.log(data2);
    });

While the result is the same, I find zip preferable to forkJoin since zip is more universal and can handle new values from the observables.

Details from the rxjs documentation:

The zip operator will subscribe to all inner observables, waiting for each to emit a value. Once this occurs, all values with the corresponding index will be emitted. This will continue until at least one inner observable completes.