extension StringExtensions on String? {
  bool isNullOrEmpty() {
    return this == null || this!.isEmpty;
  }

  bool isNotNullOrEmpty() {
    return this != null && this!.isNotEmpty;
  }

  String? isValidEmail() {
    final expression = RegExp(
      r"""^((?:[A-Za-z0-9!#$%&\'*+\-\/=?^_`{|}~]|(?<=^|\.)"|"(?=$|\.|@)|(?<=".*)[ .](?=.*")|(?<!\.)\.){1,64})(@)((?:[A-Za-z0-9.\-])*(?:[A-Za-z0-9])\.(?:[A-Za-z0-9]){2,})$""",
      multiLine: true,
    );

    if (this != null) {
      if (this!.isEmpty || !expression.hasMatch(this!)) {
        return "";
      }
    }

    return null;
  }

  bool isNotValidNumber() {
    if (isNullOrEmpty()) return true;
    if (this!.length != 12) return true;
    final numberRegExp = RegExp(r'^[+]?[0-9]+$');
    return !numberRegExp.hasMatch(this!);
  }
}