Change field parent bind.

src/accounts/accountForm.component.ts

@@ -59,12 +59,12 @@ import { Account } from './account';
 })
 export class AccountFormComponent implements  AfterViewChecked {
   @Input() account: Account;
-  @Output() onFormChanged: EventEmitter<NgForm> = new EventEmitter<NgForm>();
+  @Output() onValid: EventEmitter<boolean> = new EventEmitter<boolean>();
   @ViewChild('form') form: NgForm;
 
   constructor() {}
 
   ngAfterViewChecked() {
-    this.onFormChanged.emit(this.form);
+    this.onValid.emit(this.form.form.valid);
   }
 }