fix(typeahead): fix error on blur after init

Fix error thrown on blur before input is given

Closes valor-software#5736

src/spec/typeahead.directive.spec.ts

@@ -185,6 +185,19 @@ describe('Directive: Typeahead', () => {
         expect(fixture.debugElement.query(By.css('typeahead-container'))).toBeNull();
       })
     );
+
+    it('should not throw an error on blur', fakeAsync(() => {
+      expect(directive._container).toBeFalsy();
+      expect(directive.matches).toEqual([]);
+
+      dispatchMouseEvent(inputElement, 'click');
+      tick();
+      fixture.detectChanges();
+
+      fixture.whenStable().then(() => {
+        expect(() => directive.onBlur()).not.toThrowError();
+      });
+    }));
   });
 
   describe('onFocus', () => {

src/typeahead/typeahead.directive.ts

@@ -159,7 +159,7 @@ export class TypeaheadDirective implements OnInit, OnDestroy {
 
   // tslint:disable-next-line:no-any
   protected keyUpEventEmitter: EventEmitter<string> = new EventEmitter();
-  protected _matches: TypeaheadMatch[];
+  protected _matches: TypeaheadMatch[] = [];
   protected placement = 'bottom left';
 
   private _typeahead: ComponentLoader<TypeaheadContainerComponent>;