CODEWITHSUNDEEP
rxjs
dota2pro
dota2pro

Reputation: 7864

how to run code after 2 observables emit values and get results of emitted values?

I have 2 observables and my code is like this Stackblitz link

const obs1$ = of(1); // mock http call
const obs2$ = of(2);

obs1$.subscribe( (value1) => {
this.first = value1; // populating values from subscribe
})

obs2$.subscribe( (value2) => {
this.second = value2; // populating values from subscribe
})
forkJoin([obs1$,obs2$]).subscribe(() => {
if(this.first === 0 || this.second === 0) // checking if the values are not empty
console.log('empty')
});

How can I consolidate these 3 methods using RxJs, right now there are double http calls once from subscribe another from forkjoin. I want to populate when both observables(together) have finished and get results also to populate first and second and check their values too

Upvotes: 0

Views: 640

Answers (2)

Pawan Sharma
Pawan Sharma

Reputation: 2342

You can do that in forkJoin itself i.e -

const obs1$ = of(1).pipe(take(1)); // mock http call
const obs2$ = of(2).pipe(take(1));


forkJoin([obs1$,obs2$]).subscribe(([obs1Result, obs2Result]) => {
    this.first = obs1Result;
    this.second = obs2Result;
});

Also you may want to use combineLatest instead of forkJoin because it waits for both the observable to complete, while combineLatest emits a value, each time source observable emits a value after all observables have emitted at least one value.

Upvotes: 2

DEV
DEV

Reputation: 1736

You can directly call forkJoin and access to the resultat :

forkJoin([obs1$, obs2$]).subscribe((result) => {
    this.first = results[0];
    this.second = results[1]
    if (this.first === 0 || this.second === 0) // checking if the values are not empty
        console.log('empty')
});

Upvotes: 3

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