string method

Implementation

String? string(String key) {
  final value = map[key];
  if (value == null) {
    return null;
  }
  if (value is String) {
    return value;
  }
  if (value is num || value is bool) {
    return value.toString();
  }
  throw valueError(key, 'expected text, found ${describe(value)}.');
}