@angular/forms

PatternValidator

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.

  
    class PatternValidator extends AbstractValidatorDirective {}

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

string | RegExp

Tracks changes to the pattern bound to this directive.

ngOnChanges

void

@paramchangesSimpleChanges

@returnsvoid

validate

ValidationErrors

@paramcontrolAbstractControl<any, any>

@returnsValidationErrors

registerOnValidatorChange

void

@paramfn() => void

@returnsvoid

enabled

boolean

Determines whether this validator should be active or not based on an input. Base class implementation checks whether an input is defined (if the value is different from null and undefined). Validator classes that extend this base class can override this function with the logic specific to a particular validator directive.

@paraminputunknown

@returnsboolean