validator property
An optional method that validates an input. Returns an error string to display if the input is invalid, or null otherwise.
A PhoneNumber is passed to the validator as argument. The validator can handle asynchronous validation when declared as a Future. Or run synchronously when declared as a Function.
By default, the validator checks whether the input number length is between selected country's phone numbers min and max length.
If disableLengthCheck is not set to true, your validator returned value will be overwritten by the default validator.
But, if disableLengthCheck is set to true, your validator will have to check phone number length itself.
Implementation
final FutureOr<String?> Function(PhoneNumber?)? validator;