Angular 12 References/ Forms
🍀 Angular References

[pattern] validation directive

A directive that adds regex pattern validation to controls marked with the pattern attribute. The regex must match the entire control value.

The directive is provided with the NG_VALIDATORS multi-provider list.

Adding a pattern validator

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

<input name="firstName" ngModel pattern="[a-zA-Z ]*">

pattern#

@Input() pattern: string|RegExp

Tracks changes to the pattern bound to this directive.

validate#

validate(control: AbstractControl): ValidationErrors|null

Method that validates whether the value matches the pattern requirement.

registerOnValidatorChange#

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

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