PreferTypedPrefsWrapperRule class

Warns when SharedPreferences is used directly without a typed wrapper.

Since: v4.2.0 | Updated: v4.13.0 | Rule version: v2

Alias: typed_prefs, shared_preferences_wrapper

Direct SharedPreferences access scatters string keys throughout code and lacks type safety. Create a typed wrapper class for maintainability.

BAD:

// Scattered throughout codebase
final prefs = await SharedPreferences.getInstance();
prefs.setString('user_name', name);  // Typo-prone key
prefs.setInt('user-age', age);       // Inconsistent naming

// Elsewhere...
final name = prefs.getString('userName'); // Wrong key, returns null!

GOOD:

class UserPreferences {
  static const _keyName = 'user_name';
  static const _keyAge = 'user_age';

  final SharedPreferences _prefs;
  UserPreferences(this._prefs);

  String? get userName => _prefs.getString(_keyName);
  set userName(String? value) =>
      value == null ? _prefs.remove(_keyName) : _prefs.setString(_keyName, value);

  int get userAge => _prefs.getInt(_keyAge) ?? 0;
  set userAge(int value) => _prefs.setInt(_keyAge, value);
}