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avoid_late_keyword

Avoid late keyword

Using late disables compile time safety for what would else be a nullable variable. Instead, a runtime check is made, which may throw an unexpected exception for an uninitialized variable.

Example config:​

custom_lint:
   rules:
     - avoid_late_keyword:
       allow_initialized: false
       ignored_types:
        - AnimationController
        - ColorTween

Example​

BAD:​

class AvoidLateKeyword {
  late final int field; // LINT

  void test() {
    late final local = ''; // LINT
  }
}

GOOD:​

class AvoidLateKeyword {
  final int? field; // LINT

  void test() {
    final local = ''; // LINT
  }
}

Parameters​

allow_initialized (bool)​

Allow immediately initialized late variables.

late var ok = 0; // ok when allowInitialized == true
late var notOk; // initialized elsewhere, not allowed

ignored_types (Iterable<String>)​

Types that would be ignored by avoid-late rule

Example:

custom_lint:
  rules:
    - avoid_late_keyword:
      ignored_types:
        - ColorTween
late ColorTween tween; // OK
late int colorValue; // LINT