Angular 12 References/ Forms
🍀 Angular References

[minlength] validation directive

A directive that adds minimum length validation to controls marked with the minlength attribute. The directive is provided with the NG_VALIDATORS multi-provider list.

Adding a minimum length validator

The following example shows how to add a minimum length validator to an input attached to an ngModel binding.

<input name="firstName" ngModel minlength="4">

minlength#

@Input() minlength: string|number

Tracks changes to the minimum length bound to this directive.

validate#

validate(control: AbstractControl): ValidationErrors|null

Method that validates whether the value meets a minimum length requirement. Returns the validation result if enabled, otherwise null.

registerOnValidatorChange#

registerOnValidatorChange(fn: () => void): void

Registers a callback function to call when the validator inputs change.