Usage with createSelector

Imagine, there are two selectors in our Angular with NGRX app:

• a selector that returns the id of a current user

  export const selectCurrentUserId = createSelector(
    selectUserState,
    feature => feature.currentUserId,
  );

• a root selector for users with relationships

  export const selectUserWithCompany = rootEntity(
    selectUserState,
    relatedEntity(
      selectCompanyFeature,
      'companyId',
      'company',
    ),
  );

Then we have 3 options:

• usage of switchMap, but it is ugly

  // selecting the id of a current user
  store
    .select(selectCurrentUserId)
    .pipe(
      // selecting the user with desired relationships
      switchMap(id => store.select(selectUserWithCompany, id)),
    )
    .subscribe(user => {
      // profit
    });

• combine the selectors together via createSelector function, but it is a bit uncomfortable

  export const selectCurrentUser = createSelector(
    // selecting the whole store
    s => s,
    // selecting the id of a current user
    selectCurrentUserId,
    // selecting the user with desired relationships
    selectUserWithCompany,
  );
  
  store.select(selectCurrentUser).subscribe(user => {
    // profit
  });

• pass an id selector as a parameter, what is the best choice and quite short

  // selecting the user with desired relationships
  store
    .select(selectUserWithCompany, selectCurrentUserId)
    .subscribe(user => {
      // profit
    });