Dictionary constructor

Dictionary([ Mapping? dict ])

Type Erasure

Implementation

Dictionary([Mapping? dict])
    : _map = dict == null ? <String, dynamic>{}.asMutableMapping()
    : dict is Mapper ? dict.toMap()
    : dict.asMutableMapping() {
  // Ensure that all keys are of type String.
  assert(() {
    try {
      // check type
      final _ = _map as MutableMapping<String, dynamic>;
    } catch (_) {
      // type error
      return false;
    }
    if (dict != null) {
      // check all keys
      for (final key in dict.keys) {
        if (key is! String) {
          // key error
          return false;
        }
      }
    }
    // OK
    return true;
  }(), '⚠️ Debug hint: underlying map debug type‑argument is NOT Map<String,dynamic>. '
      'It may be Map<dynamic,dynamic>.\n'
      'Ensure all keys are String. map=$dict');
}