The material select works, but it outputs a lot of erros to the console, because the event in the closeSelect function is always undefined.

Following code fixes the issue:

@HostListener(\'document:click\', [\'$event\']) closeSelect(event: any) { 
  if (!this.isChild(event.target) && this.isOpen) { 
    this.closeDropdown(); 
  } 
};