Question: I'm writing an app in Angular 2 and I want to execute several http requests and run a function on the responses.

In Angular 1, I would write something like `$q.all([$http.get(...), $http.get(...), ...]).then(doSomethingWithResponses);`

But Angular 2 returns RxJS Observables and after a bunch of reading I still can't figure out how to get the responses of several http requests. How can this can be done?

Answer: 
As @Eric Martinez pointed out, there is [forkJoin](https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/operators/forkjoin.md). forkJoin runs all observable sequences in parallel and collect their last elements.

```
Rx.Observable.forkJoin([a,b]).subscribe(t=> {
        var firstResult = t[0];
        var secondResult = t[1];
});

```
I'm learning RxJS and I was trying to do the same thing with RxJS v5

It seems like we don't have `forkJoin` on v5 anymore, so here's how I got it working (works with `flatMap` or `mergeMap`, which are aliases):

```
const callOne = value =>
    new window.Promise(resolve =>
        setTimeout(() => resolve(value + 10), 3000)
    );

const callTwo = value =>
    new window.Promise(resolve =>
        setTimeout(() => resolve(value + 20), 1000)
    );

Rx.Observable
    .of(2)
    .do(() => console.log('querying...'))
    .mergeMap(number =>
        Rx.Observable.zip(
            Rx.Observable.fromPromise(callOne(number)),
            Rx.Observable.fromPromise(callTwo(number))
        )
    ).concatAll()
    .subscribe(createSubscriber('promises in parallel'));

```