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) {
    final startWithText = useTrim ? startWith.trim() : startWith;
    final text = useTrim ? value.trim() : value;
    if (!caseSensitive) {
      if (!text.toLowerCase().startsWith(startWithText.toLowerCase())) {
        return getErrorMessage(
          EasyValidatorMessages.instance.startWith,
          startWith,
        );
      }
    } else {
      if (!text.startsWith(startWithText)) {
        return getErrorMessage(
          EasyValidatorMessages.instance.startWith,
          startWith,
        );
      }
    }
  }
  return null;
}