> For the complete documentation index, see [llms.txt](https://soufatn.gitbook.io/rxjs-book/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://soufatn.gitbook.io/rxjs-book/summary/observable/observable_methods/forkjoin.md).

# forkJoin

![forkJoin](http://reactivex.io/documentation/operators/images/forkJoin.png)

Runs all observable sequences in parallel and collect their last elements.

## Arguments

1. `args` *(`Arguments` | `Array`)*: An array or arguments of Observable sequences or Promises to collect the last elements for.
2. `resultSelector`: *(`Function`)* - The result selector from all the values produced. If not specified, `forkJoin` will return the results as an array.

## Returns

*(`Observable`)*: An observable sequence with an array collecting the last elements of all the input sequences or the result of the result selector if specified.

## [Example](http://jsbin.com/sudura/2/edit?js,console)

```javascript
/* Using observables and Promises */
var source = Rx.Observable.forkJoin(
    Rx.Observable.return(42),
    Rx.Observable.range(0, 10),
    Rx.Observable.fromArray([1,2,3]),
    RSVP.Promise.resolve(56)
);

var subscription = source.subscribe(
  x => console.log(`onNext: ${x}`),
  e => console.log(`onError: ${e}`),
  () => console.log('onCompleted'));

// => onNext: [42, 9, 3, 56]
// => onCompleted
```

## Example