How to change the validation of a field?

Question

Angular

I do not use reactive forms - you need to validate the input field either asynchronously with the server call, or according to a given regex rule. You can write two directives, but how to substitute?

<input type="text" validateAsync>
<input type="text" validateNoAsync>

Answer 1

how to substitute?

<input *ngIf="sync" type="text" validateAsync>
<input *ngIf="!sync" type="text" validateNoAsync>