Built-in and Custom Validators

Angular provides built-in validators and also allows custom validators.

Built-in validators include:

• required
• minlength
• maxlength
• email
• pattern

Example:

import { FormControl, Validators } from "@angular/forms";

email = new FormControl("", [Validators.required, Validators.email]);

Custom validator example:

import { AbstractControl, ValidationErrors } from "@angular/forms";

export function forbiddenName(control: AbstractControl): ValidationErrors | null {
  return control.value === "admin" ? { forbiddenName: true } : null;
}