CODEWITHSUNDEEP
typescriptrxjs6
Pavel
Pavel

Reputation: 2101

How to union two Observable. Rx 6.2.2

I have two calls to the backend and I need handle result only when both responses will be ready:

this.historyService.fetchBalance().subscribe((balance: Balance[]) => {
    this.servicesBalance = balance;
});

this.historyService.fetchOuts().subscribe((outs: History[]) => {
    this.outHistories = outs;
});

I know forkJoin method but it returns Array and I lost types, something like this:

...subscribe([v1, v2] => ...)

I want to save types of returning values something like this:

...subscribe(balance: Balance[], outs: History[] => ...)

How to union Observables in my case?

myQuestionUnionMethod(
    this.historyService.fetchBalance(),
    this.historyService.fetchOuts()
)
    .subscribe(balance: Balance[], outs: History[] => ...)

Upvotes: 0

Views: 419

Answers (1)

meriton
meriton

Reputation: 70564

Have you tried zip? It seems properly typed:

export function zip<T, T2>(v1: ObservableInput<T>, v2: ObservableInput<T2>): Observable<[T, T2]>;
export function zip<T, T2, T3>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>): Observable<[T, T2, T3]>;
export function zip<T, T2, T3, T4>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>): Observable<[T, T2, T3, T4]>;
export function zip<T, T2, T3, T4, T5>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, v5: ObservableInput<T5>): Observable<[T, T2, T3, T4, T5]>;
export function zip<T, T2, T3, T4, T5, T6>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>, v5: ObservableInput<T5>, v6: ObservableInput<T6>): Observable<[T, T2, T3, T4, T5, T6]>;

On second thought, forkJoin also seems properly typed:

export function forkJoin<T>(sources: [ObservableInput<T>]): Observable<T[]>;
export function forkJoin<T, T2>(sources: [ObservableInput<T>, ObservableInput<T2>]): Observable<[T, T2]>;
export function forkJoin<T, T2, T3>(sources: [ObservableInput<T>, ObservableInput<T2>, ObservableInput<T3>]): Observable<[T, T2, T3]>;
export function forkJoin<T, T2, T3, T4>(sources: [ObservableInput<T>, ObservableInput<T2>, ObservableInput<T3>, ObservableInput<T4>]): Observable<[T, T2, T3, T4]>;
export function forkJoin<T, T2, T3, T4, T5>(sources: [ObservableInput<T>, ObservableInput<T2>, ObservableInput<T3>, ObservableInput<T4>, ObservableInput<T5>]): Observable<[T, T2, T3, T4, T5]>;
export function forkJoin<T, T2, T3, T4, T5, T6>(sources: [ObservableInput<T>, ObservableInput<T2>, ObservableInput<T3>, ObservableInput<T4>, ObservableInput<T5>, ObservableInput<T6>]): Observable<[T, T2, T3, T4, T5, T6]>;
export function forkJoin<T>(sources: Array<ObservableInput<T>>): Observable<T[]>;

What makes you think the return value is not properly typed? Do you have an example where you "lost types"?

Upvotes: 2

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