validate method

String? validate({ required String label, required String? value, })

Executes each of the validators, in order. This will fail-fast where it will stop walking the list as soon as any validator returns an error.

A return value of null means all validators passed. A non-null response is the error message that can be displayed to the user.

The context is used to attempt to find a valid Translator on the widget tree. This allows applications the ability to provide their own translated strings for error messages.

See also:

• https://pub.dev/packages/static_translations

Implementation

String? validate({
  required String label,
  required String? value,
}) {
  String? error;
  for (var v in validators) {
    error = v.validate(
      label: label,
      value: value,
    );

    if (error?.isNotEmpty == true) {
      break;
    }
  }

  // Normalize empty strings to `null` for API consistency.
  return error?.isEmpty == true ? null : error;
}