forkJoin is deprecated: resultSelector is deprecated, pipe to map instead

Question

I\'m working on an Angular 6 project.

Running ng lint gives the following Warning:

"forkJoin is deprecated: resultSelector is deprecated,

Answer 1

forkJoin should work. Which rxjs version are you using? Latest version should be doing this:

import { of, combineLatest, forkJoin } from 'rxjs';
import { map, mergeAll } from 'rxjs/operators';

Here the working code:

import { of, forkJoin } from 'rxjs';

const observables = [of('hi'), of('im an'), of('observable')];

const joint = forkJoin(observables);

joint.subscribe(
  s => console.log(s) 
)

Should output:

["hi", "im an", "observable"]

I tried reproducing this but I see no warning:

https://stackblitz.com/edit/angular-v4nq3h?file=src%2Fapp%2Fapp.component.ts

Answer 2

This is because they the RXJS team puts their deprecation warnings at the top of the file.

 import { Observable } from '../Observable';
import { ObservableInput, ObservedValueOf, ObservedValuesFromArray, SubscribableOrPromise } from '../types';

/** @deprecated Use the version that takes an array of Observables instead */
export declare function forkJoin<T>(v1: SubscribableOrPromise<T>): Observable<[T]>;
/** @deprecated Use the version that takes an array of Observables instead */
export declare function forkJoin<T, T2>(v1: ObservableInput<T>, v2: ObservableInput<T2>): Observable<[T, T2]>;
/** @deprecated Use the version that takes an array of Observables instead */
export declare function forkJoin<T, T2, T3>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>): Observable<[T, T2, T3]>;
/** @deprecated Use the version that takes an array of Observables instead */
export declare function forkJoin<T, T2, T3, T4>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>): Observable<[T, T2, T3, T4]>;
/** @deprecated Use the version that takes an array of Observables instead */
export declare function forkJoin<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]>;
/** @deprecated Use the version that takes an array of Observables instead */
export declare function forkJoin<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]>;
export declare function forkJoin<A>(sources: [ObservableInput<A>]): Observable<[A]>;
export declare function forkJoin<A, B>(sources: [ObservableInput<A>, ObservableInput<B>]): Observable<[A, B]>;
export declare function forkJoin<A, B, C>(sources: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>]): Observable<[A, B, C]>;
export declare function forkJoin<A, B, C, D>(sources: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>, ObservableInput<D>]): Observable<[A, B, C, D]>;
export declare function forkJoin<A, B, C, D, E>(sources: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>, ObservableInput<D>, ObservableInput<E>]): Observable<[A, B, C, D, E]>;
export declare function forkJoin<A, B, C, D, E, F>(sources: [ObservableInput<A>, ObservableInput<B>, ObservableInput<C>, ObservableInput<D>, ObservableInput<E>, ObservableInput<F>]): Observable<[A, B, C, D, E, F]>;
export declare function forkJoin<A extends ObservableInput<any>[]>(sources: A): Observable<ObservedValuesFromArray<A>[]>;
export declare function forkJoin(sourcesObject: {}): Observable<never>;
export declare function forkJoin<T, K extends keyof T>(sourcesObject: T): Observable<{
    [K in keyof T]: ObservedValueOf<T[K]>;
}>;
/** @deprecated resultSelector is deprecated, pipe to map instead */
export declare function forkJoin(...args: Array<ObservableInput<any> | Function>): Observable<any>;
/** @deprecated Use the version that takes an array of Observables instead */
export declare function forkJoin<T>(...sources: ObservableInput<T>[]): Observable<T[]>;

Answer 3

This gave this warning:

forkJoin is deprecated: Use the version that takes an array of Observables instead (deprecation)

 forkJoin(this.getProfile(), this.getUserFirstName(), this.getUserLastName())
      .subscribe(([res1, res2, res3]) => {
        this.OnboardingUser = res1;
        this.userFirstName = res2;
        this.userLastName = res3;
      }, err => { console.log(err); });

I have changed it like so: i.e. added []

 forkJoin([this.getProfile(), this.getUserFirstName(), this.getUserLastName()])
      .subscribe(([res1, res2, res3]) => {
        this.OnboardingUser = res1;
        this.userFirstName = res2;
        this.userLastName = res3;
      }, err => { console.log(err); });

Answer 4

forkJoin(observable1, observable2)       > WORKING - deprecation warning
forkJoin([observable1, observable2])     > WORKING - no warning

Answer 5

I was able to fix this by getting rid of the ellipsis:

forkJoin(observables).subscribe();

As long as observables is already an array, it should have the same result.

Answer 6

accroding to forkJoin.d.js , the forkJoin(...args) is deprecated, you can write the other way. for your source code, since you already have an array with same type, just pass your array will be OK.

//forkJoin.d.js
import { Observable } from '../Observable';
import { ObservableInput } from '../types';
export declare function forkJoin<T>(sources: [ObservableInput<T>]): Observable<T[]>;
export declare function forkJoin<T, T2>(sources: [ObservableInput<T>, ObservableInput<T2>]): Observable<[T, T2]>;
export declare function forkJoin<T, T2, T3>(sources: [ObservableInput<T>, ObservableInput<T2>, ObservableInput<T3>]): Observable<[T, T2, T3]>;
export declare function forkJoin<T, T2, T3, T4>(sources: [ObservableInput<T>, ObservableInput<T2>, ObservableInput<T3>, ObservableInput<T4>]): Observable<[T, T2, T3, T4]>;
export declare 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 declare 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 declare function forkJoin<T>(sources: Array<ObservableInput<T>>): Observable<T[]>;
export declare function forkJoin<T>(v1: ObservableInput<T>): Observable<T[]>;
export declare function forkJoin<T, T2>(v1: ObservableInput<T>, v2: ObservableInput<T2>): Observable<[T, T2]>;
export declare function forkJoin<T, T2, T3>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>): Observable<[T, T2, T3]>;
export declare function forkJoin<T, T2, T3, T4>(v1: ObservableInput<T>, v2: ObservableInput<T2>, v3: ObservableInput<T3>, v4: ObservableInput<T4>): Observable<[T, T2, T3, T4]>;
export declare function forkJoin<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 declare function forkJoin<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]>;
/** @deprecated resultSelector is deprecated, pipe to map instead */
export declare function forkJoin(...args: Array<ObservableInput<any> | Function>): Observable<any>;
export declare function forkJoin<T>(...sources: ObservableInput<T>[]): Observable<T[]>;