Validation with the input and select components

Angular provides three different ways of building forms in our applications:

• Template-driven approach: This approach allows us to build forms with very little to no application code required
• Model-driven (or reactive) approach using low-level APIs: In this approach, we create our forms as testable without a DOM being required
• Model-driven with a higher level API: This approach uses a higher level API called FormBuilder.

PrimeNG created most of the input and select components with model-driven form support. Because of this, all input and select components are eligible for validation.

Let's take an example of a registration form with firstname, lastname, password, address, phone, and gender fields with validation support. PrimeNG components are backed by a model-driven API with FormBuilder, which groups all of the form controls to create a registration form, as shown here:

this.registrationform = this.formBuilder.group({
    'firstname...