Angular 8: Grandparent Component detect when User Focus out of grandchild Component Textbox

问题

I have a Nested Grantparent Smart Component, Parent Component with a Form, and a Grandchild Component with ZipCode textbox.

How do I make it so, when user clicks out of the grandchild Component Textbox, Grandparent Component will know? Need to run business logic after user clicks out of textbox. Currently textbox is based off Material Angular wrapper.

so

1. Grand Smart Component
2. Parent Form
3. Textbox

Parent Component has Formbuilder and many textboxes, sample below

this.editAddressForm = this.formBuilder.group({
   'city': [null,[Validators.maxLength(50)]],
   'zipCode': [null,[Validators.maxLength(10)]],


<app-input-textbox class = "zipcodeclass" div="zipcode" formControlName = "zipCode">

来源：https://stackoverflow.com/questions/59779037/angular-8-grandparent-component-detect-when-user-focus-out-of-grandchild-compon