angular2 asynchronous function executation

We may need more info but let say you have 2 http calls and you want make them "synchronous" (one first and then the second one). I would recommend using ReactiveX JavaScript, you can import by including:

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

With mergeMap operator you are able to start a "second task" (new observable) taking the first one's result as input.

So, for instance, I need to check address before updating my user profile. I have 2 http calls; one for the address check and another one for updating the user profile, so I would do:

this.http.get(geolocationGoogleUrl, this._customAddress)
    .mergeMap((location: any)=>{ // First http response
        console.log(location);
        // Do your stuff before second call

        return this.http.patch(patchUrl, localAddress); // Use frist http response as input
    }).subscribe((updatedUser)=>{ // Second http response
        this._user = updatedUser;
    });

As you noticed, you need to subscribe to a observable in order to trigger the call.