CODEWITHSUNDEEP
typescript
Anand
Anand

Reputation: 41

Function overloads with optional parameters

I am experimenting with function overloads in Typescript and I am getting the following error:

Error:(2, 5) TS2394: Overload signature is not compatible with function implementation.

I don't understand how to resolve this error. Any help would be appreciated.

create(key: string | TextKeys, reKey: string | TextKeys, params?: ObjectLiteral<string>, subkeys?: { [key: string]: string }, selector?: Selector): Either<EError, (AOutput | ROutput)[]>;
create(key: string | TextKeys, params?: ObjectLiteral<string>, subkeys?: { [key: string]: string }, selector?: Selector): Either<EError, AOutput>;
create(key: string | TextKeys, reKey?: string | TextKeys, params?: ObjectLiteral<string>, subkeys?: { [key: string]: string }, selector: Selector = selectRandom) {
    const output: Either<EError, AOutput> = this.createAOutputs(key, params, subkeys).map(selector);
    if (reKey !== undefined) {
        return List.fromArray([output, this.createROutputs(reKey, params, subkeys)]).sequenceEither<EError, AOutput | ROutput>().map(arr => _.flatten(arr.toArray())) as Either<EError, (AOutput | ROutput)[]>;
    } else {
        return output;
    }
}

Upvotes: 1

Views: 49

Answers (1)

basarat
basarat

Reputation: 275997

I don't understand how to resolve this error. Any help would be appreciated.

Your last function signature MUST work for every possible overload. A quick hack to show what will work: 

create(key: string | TextKeys, reKey: string | TextKeys, params?: ObjectLiteral<string>, subkeys?: { [key: string]: string }, selector?: Selector): Either<EError, (AOutput | ROutput)[]>;
create(key: string | TextKeys, params?: ObjectLiteral<string>, subkeys?: { [key: string]: string }, selector?: Selector): Either<EError, AOutput>;
create(...iWorkWithAllOptions:any[]) { // NOTICE 
    // implement
}

Upvotes: 1

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