alphanumeric static method

String? Function(String?) alphanumeric({
  1. String? message,
})

Validates alphanumeric characters

Implementation

static String? Function(String?) alphanumeric({String? message}) {
  return (String? value) {
    if (value == null || value.trim().isEmpty) {
      return null;
    }

    if (!RegExp(r'^[a-zA-Z0-9\s]+$').hasMatch(value)) {
      return message ?? _defaultMessages['alphanumeric'];
    }

    return null;
  };
}