typeahead.ts

search(text$: Observable<string>) {
    return text$.pipe(
      debounceTime(500),
      distinctUntilChanged(),
      mergeMap((term) => {
          // this.chatService.setPseudpInput(term);
          return this.chatService.getUserByPseudo(term)
          .pipe(
              map(values => {
                    // states = values;
                    return term.length < 2 ? [] : states.filter(v => v);
                })
          );
        }
      ));
  }