NgRx EntityState - compiler error *TS2769: No overload matches this call

Question

I have a compile error I do not understand.

If I have an EntityState And store Persons in the store then trying to see if a specific id does exist, I tried follwoing code:

            this.store.select(fromPersonSelectors.selectPersonIds)
            .pipe(tap(theIds => console.log("pipe-tab theIds"+typeof theIds)))
            .pipe(filter(theIds => {
                if (theIds !== null && isNumberArray(theIds)) {
                    theIds.find((oneId:number) => oneId.toFixed(0) === this.personId)
                    // !==this.personId
                }
            }), take(1))

...

export function isNumberArray(array: string[] | number[]): array is number[] {
return typeof array[0] === 'number';

}

selectPersonIds is returning from the entity library, from '@ngrx/entity', which is used by the store:

export interface EntitySelectors<T, V> {
selectIds: (state: V) => string[] | number[];

V is the PersonDTO

A compile error I do not understand comes with the second .pipe (.pipe(filter(theIds => {) stating:

TS2769: No overload matches this call.   Overload 1 of 5, '(predicate: (value: string[] | number[], index: number) => value is string[] | number[]): OperatorFunction<string[] | number[], string[] | number[]>', gave the following error.     Argument of type '(theIds: string[] | number[]) => void' is not assignable to parameter of type '(value: string[] | number[], index: number) => value is string[] | number[]'.       Signature '(theIds: string[] | number[]): void' must be a type predicate.   Overload 2 of 5, '(predicate: BooleanConstructor): OperatorFunction<string[] | number[], string[] | number[]>', gave the following error.     Argument of type '(theIds: string[] | number[]) => void' is not assignable to parameter of type 'BooleanConstructor'.       Types of parameters 'theIds' and 'value' are incompatible.         Type 'T' is not assignable to type 'string[] | number[]'.           Type 'T' is not assignable to type 'number[]'.   Overload 3 of 5, '(predicate: (value: string[] | number[], index: number) => boolean): MonoTypeOperatorFunction<string[] | number[]>', gave the following error.     Argument of type '(theIds: string[] | number[]) => void' is not assignable to parameter of type '(value: string[] | number[], index: number) => boolean'.       Type 'void' is not assignable to type 'boolean'

Perhaps someone knows, tnx in advance.

Answer 1

filter needs to return a boolean. The code that is shared doesn't return something within filter, and is thus a void. That's why you get the error Type 'void' is not assignable to type 'boolean'.