core.js:15723 ERROR TypeError: Cannot read property 'filter' of undefined
at t.project (mention.component.ts:41)
at t._next (map.js:35)
at t.next (Subscriber.js:53)
at t._next (distinctUntilChanged.js:55)
at t.next (Subscriber.js:53)
at t.debouncedNext (debounceTime.js:48)
at te (debounceTime.js:62)
at t._execute (AsyncAction.js:64)
at t.execute (AsyncAction.js:52)
at t.flush (AsyncScheduler.js:43)