How do I implement synchronous validators in Angular?

How do I implement synchronous validators in Angular?

To implement synchronous validators in Angular, you can use the built-in validators from @angular/forms. For example, you can use Validators.required to ensure a field is not empty.

Can you show me an example of using multiple validators?

Sure! You can combine validators like this: Validators.compose([Validators.required, Validators.minLength(3)]) to require a minimum length of 3 characters.

What if I want to create a custom synchronous validator?

You can create a custom validator by defining a function that returns either null (if valid) or an error object (if invalid). Here's a simple example: function customValidator(control: AbstractControl) { return control.value === 'invalid' ? { invalid: true } : null; }.

How do I apply this custom validator to a form control?

You can apply it like this: this.form = this.fb.group({ myControl: ['', customValidator] }); where fb is your FormBuilder instance.