How do I access mat menu trigger from typescript

Figured it out. I just needed to use MatMenuTrigger instead of the element id.

@ViewChild(MatMenuTrigger) notificationMenuBtn: MatMenuTrigger;

If you really need to use an id (When you have several MatMenuTrigger)

@ViewChild('notificationMenuBtn', {read: MatMenuTrigger}) protected notificationMenuBtn : MatMenuTrigger;