How to make a method generic?

Question

typescript

public getPayerTypes(): Observable<PayerType[]> {
    return this.http.get<PayerTypes>('getPayerTypes')
      .pipe(
        pluck('data'),
        catchError(this.handleError)
      );
  }

Here's something that doesn't work:

private httpGet<T, K>(url: string): Observable<T> {
    return this.http.get<PayerTypes>('getPayerTypes')
      .pipe(
        pluck('data'),
        catchError(this.handleError)
      );
  }

Answer 1

What for? You explicitly indicate that the result is Observable<PayerTypes>. It cannot be anything else, and it does not depend on anything. Why there url?
Or maybe you mean something like this:

type Urls = {
    getPayerTypes: PayerTypes;
    getNPCTypes: NPCTypes;
}

private httpGet<K extends keyof Urls>(url: K): Observable<Urls[K]> {
  return this.http.get<Urls[K]>(url)
    .pipe(
      pluck('data'),
      catchError(this.handleError)
    );
}