valueChanges.ts

this.searchReposFormControl.valueChanges
  .subscribe((searchString) => {
    if (searchString) {
      this.searchType = SearchType.REPOS;
      this.searchSubject$.next(searchString);
    }
  });

this.searchUsersFormControl.valueChanges
  .subscribe((searchString) => {
    if (searchString) {
      this.searchType = SearchType.USERS;
      this.searchSubject$.next(searchString);
    }
  });