Type 'Observable<Object>' is not assignable to type 'Observable<boolean>'

3
votes

I have an error: Type 'Observable' is not assignable to type 'Observable'. Type 'Object' is not assignable to type 'boolean'.

  deleteUser(userId: string): Observable<boolean> {
    return this.httpClient
      .delete(url, this.getHttpOptions())
      .map(res => {
        return res;
      })
      .catch(this.handleError);
  }

I got the type of res as a boolean when I tried to print it.

3
angularobservableangular7type-mismatch
Try that: return this.httpClient.delete<boolean>(...), and you won't need the map – David
This error should be thrown from different place. Check the code where you are using this deleteUser method. And make sure you have set Observable<boolean> in there too; Or you can try .delete<boolean>(url, this.getHttpOptions()); This should work too – zgabievi

3 Answers

4
votes

At compile time, TypeScript doesn't know what actually comes from API call, it infers it from declarations and function signatures.

      .delete<boolean>(url, this.getHttpOptions())

should work.

(And yes, ditch the map).

1
votes

The type of res needs to be boolean, by default it will be any. Replace map by following :

map((res:boolean) => {
    return res;
  })
0
votes

You can fix it by removing your .map (which doesn't do anything):

deleteUser(userId: string): Observable<boolean> {
  return this.httpClient
    .delete(url, this.getHttpOptions())
    .catch(this.handleError);
}