Regex

The Regex rule checks that a field's value matches a pattern you supply, and the pattern can be passed either as a plain string or as a native RegExp object — whichever is more convenient in the binding mode you're using. It's the escape hatch for custom formats the built-in rules don't cover, such as requiring a password to contain at least one digit with regex:(?=.*[0-9]), enforcing a specific product-code layout, or matching a company-internal ID scheme. When the requirement is really 'must not match' rather than 'must match', the Not Regex rule flips the same mechanism to the opposite check.

#Directive Code Snippet

<!DOCTYPE html> 
<html lang="en"> 
    ...
    <form (ngSubmit)="onSubmit(form)" #form="ngForm">
		<input regex="<EXPRESSION>" type="text" name="<name>" [(ngModel)]="<name>" #<name>="ngModel">
        <ng-absolute-validator [formInstance]="<name>"></ng-absolute-validator>
	</form>
    ...
</html>

#Chain Rule Code Snippet

<!DOCTYPE html> 
<html lang="en"> 
    ...
    <form (ngSubmit)="onSubmit(form)" #form="ngForm">
		<input rule="regex:<EXPRESSION>" type="text" name="<name>" [(ngModel)]="<name>" #<name>="ngModel">
        <ng-absolute-validator [formInstance]="<name>"></ng-absolute-validator>
	</form>
    ...
</html>

#Reactive Form Code Snippet

//component.ts 
export class ReactiveComponent{

	public form  !: FormGroup;

  	constructor(
      	private fb : FormBuilder,
		private rv : ReactiveValidator,
	){this.generteForm()}

	generteForm(){
		this.form = this.fb.group({
			<name> : ['',this.rv.map('regex:<EXPRESSION>',<CUSTOM_MESSAGE>)]
		})
	}
}

//component.html 
<!DOCTYPE html> 
<html lang="en"> 
    ...
    <form [formGroup]="form">
		<input type="text" name="<name>" formControlName="<name>">
        <ng-absolute-validator [formInstance]="form.get(<name>)"></ng-absolute-validator>
	</form>
    ...
</html>