RxJS - Multiple sources for .withLatestFrom

41
votes

I want to merge the latest emitted values from multiple Observables, so right now I'm using .withLatestFrom. Except, it nests the data together in nested arrays instead of pushing the data into a new array value. Example code below.

Any ideas on how I can retrieve multiple Observable emits using .withLatestFrom?

source0
  .withLatestFrom(source1)
  .withLatestFrom(source2)
  .withLatestFrom(source3)
  .map((data) => { console.log(data) });
2
angularrxjsngrx

2 Answers

94
votes

withLatestFrom supports multiple observables:

.withLatestFrom(source1, source2, source3)
.map((data) => { console.log(data) });

-> [val, value1, value2, value3]

It also supports function as it's last parameter, so you can get values other than arrays:

observable$
    .withLatestFrom(source1, source2, (val, one, two) => {
        return {val: val, one: one, two: two};
     });
7
votes

withLatestFrom accepts multiple observables. so you can write it like:

let obs1$ = Rx.Observable.of('a');
let obs2$ = Rx.Observable.of('b');

Rx.Observable.interval(1000)
  .withLatestFrom(obs1$, obs2$)
  .subscribe(x=>console.log(x))