How does passing data between angular components work?

Question

Angular

They write what is needed in the parent component A in the child . But for some reason, Angular requires me to assign some value to var in the child component, although there is no such value in any instruction, I have to write empty values ​​or integer objects each time if it is an interface, is there not such a bad way?
<a [var]="value" routerLink="/page">link</a>
@Input() var:string

Answer 1

Well
, in general, a useful thing, and it is desirable to write your code so that you do not have to turn it off.