validateVariableName static method

String? validateVariableName(
  1. String name
)

Implementation

static String? validateVariableName(String name) {
  // 1
  if (name.isEmpty) {
    return 'Variable names must not be empty.';
  }
  // 2
  var numberExp = RegExp(r'[0-9]');
  if (name.startsWith(numberExp)) {
    return 'Variable names must not start with a digit.';
  }
  // 3
  final allowedCharacters = RegExp(r'^[a-zA-Z0-9\_\$]+$');
  if (!name.contains(allowedCharacters)) {
    return "Variable names can only contain letters, digits, the dollar sign '\$' or underscore '_'.";
  }

  var allowedExp = RegExp(r'[a-zA-z\_\$]');
  if (name.startsWith(allowedExp)) {
    return null;
  }

  return 'Variable names must start with a letter.';
}