selectParams not support optional parameters

[Pulsifi-ZiHao]

Description

when I try to upgrade from akita-ng-router-store, I have using selectParams which the parameter is an optional and there have no problem because when the parameter is undefined, selectParams still will emit the value, but elf-ng-router-store not supporting this. I want to suggest remove the filterNil operator from the selectParams method.

Proposed solution

 selectParams<T extends string>(
names?: string | string[]
): Observable<T | T[] | Params | null> {
  if (names === undefined) {
    return store.pipe(sliceState('params'));
  }

const _select = (p: string) =>
  store.pipe(
    sliceState<RouterState>('params'),
    pluck(p),
    filterNil() <--- remove this line
  );

if (Array.isArray(names)) {
  const sources = names.map(_select);
  return combineLatest(sources);
}

return _select(names).pipe(distinctUntilChanged());

}

Alternatives considered

no other alternatives

Do you want to create a pull request?

No