Observable forkjoin subscribe types

Question

I'm making 2 API requests calls with typed responses, combining them into a single Observable.forkJoin. I want to get both results in different typed variables.

var observableOrganization: Observable<Organization> = this.getOrganizationDetails();
var observablePromotion: Observable<Promotion[]> = this.getPromotions();

Observable.forkJoin([ observableOrganization, observablePromotion])
    .subscribe(
        response => {
            organization: Organization = response[0];
            promotions: Promotion[] = response[1];
        },
        error => {
            // ...
        }
    );

How can I reach typed results in single subscribe response?

By "typed" you mean eg. this `Observable`? Or you want to merge the results? — martin, Sep 18 '17 at 12:00
I don't understand what you want to achieve or what doesn't work to be honest... — martin, Sep 18 '17 at 12:02
in the .subscribe((response)) , the response type is Organization[] by default. This is wrong, I made 2 api calls which gives me 2 different types(Organization and Promotion[]), not Organization[] — Jorge Guerola, Sep 18 '17 at 12:06
This is what you're doing https://github.com/ReactiveX/rxjs/blob/master/src/observable/ForkJoinObservable.ts#L23, it returns `Observable<[Organization, Promotion[]]>` — martin, Sep 18 '17 at 12:16

score 32 · Answer 1 · edited Aug 25 '20 at 05:09

32

Use es6 destructuring also you can add types if they dont automatically assigned

 Observable.forkJoin([ observableOrganization, observablePromotion])
        .subscribe(([org, prom]: [Organization, Promotion[]]) => {
            organization:Organization = org;
            promotions: Promotions[] = prom
        },
        error => {
            //error here
        });

edited Aug 25 '20 at 05:09

Developer Marius Žilėnas

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answered Sep 18 '17 at 11:56

alexKhymenko

5,450
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thanks for help, but I cant make this compile: .subscribe([response1, prom]: [Organization, Promotion[]]) => { }); – Jorge Guerola Sep 18 '17 at 12:02
1

In the .subscribe([org, prom]: gets this error: Argument of type 'any[]' is not assignable to parameter of type '(value: Organization[]) => void'. – Jorge Guerola Sep 18 '17 at 12:09
The problem probably in this lines of code var observableOrganization: Observable = this.getOrganizationDetails(); var observablePromotion: Observable = this.getPromotions(); – alexKhymenko Sep 18 '17 at 12:11
check the types of this functions – alexKhymenko Sep 18 '17 at 12:12
or update the question with full code will be easier. – alexKhymenko Sep 18 '17 at 12:12

slartidan · Answer 2 · 2019-05-17T05:30:32.547

8

forkJoin will only return "nice" types, when the requests are explicitly declared as ObservalbleInput.

I personally prefer this syntax, using the destructing language feature:

const requests: [ObservableInput<Organization>, ObservableInput<Promotion[]>] = [observableOrganization, observablePromotion];
Observable.forkJoin(requests)
    .subscribe(
        ([organization, promotions]: [Organization, Promotion[]]) => {
            // use organization and promotions here
        },
        error => {
            // ...
        }
    );

edited May 17 '19 at 05:30

answered Oct 24 '18 at 13:35

slartidan

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Isn't this rather due to the fact that you're explicitly typing your subscribe value here by doing : [Organization, Promotion[]. I didn't get this working in any case. – rumblefx0 Jul 05 '19 at 12:27
@rumblefx0 Are you sure, you used `ObservableInput` for *all* requests? It worked for me quite well. – slartidan Jul 05 '19 at 14:02
Hmm, can you show how you instantiate observableOrganization & observablePromotion please? – rumblefx0 Jul 09 '19 at 07:25

Observable forkjoin subscribe types

2 Answers2