validate method

@override String? validate(String? value)

Validates the given value and returns an error message if the value is invalid.

Implementation

@override
String? validate(String? value) {
  if (value != null) {
    if (caseSensitive) {
      if (!value.contains(contains)) {
        return getErrorMessage(
          EasyValidatorMessages.instance.contains,
          contains,
        );
      }
    } else {
      if (!value.toLowerCase().contains(contains.toLowerCase())) {
        return getErrorMessage(
          EasyValidatorMessages.instance.contains,
          contains,
        );
      }
    }
  }
  return null;
}