Validator
interface
An interface implemented by classes that perform synchronous validation.
interface Validator {
validate(control: AbstractControl): ValidationErrors | null
registerOnValidatorChange(fn: () => void)?: void
}
Child interfaces
AsyncValidator
Class implementations
EmailValidator
MaxLengthValidator
MinLengthValidator
PatternValidator
RequiredValidator
CheckboxRequiredValidator
Methods
validate() | |||
---|---|---|---|
Method that performs synchronous validation against the provided control. | |||
validate(control: AbstractControl): ValidationErrors | nullParameters
Returns
|
registerOnValidatorChange() | |||
---|---|---|---|
Registers a callback function to call when the validator inputs change. | |||
registerOnValidatorChange(fn: () => void)?: voidParameters
Returns
|
Usage notes
Provide a custom validator
The following example implements the Validator
interface to create a validator directive with a custom error key.
@Directive({
selector: '[customValidator]',
providers: [{provide: NG_VALIDATORS, useExisting: CustomValidatorDirective, multi: true}]
})
class CustomValidatorDirective implements Validator {
validate(control: AbstractControl): ValidationErrors|null {
return {'custom': true};
}
}
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Licensed under the Creative Commons Attribution License 4.0.
https://v9.angular.io/api/forms/Validator