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avoid-unnecessary-collections

added in: 1.15.0
warning
Pro+
preset: recommended

Warns when a collection literal can be replaced by its first and only element.

Example​

❌ Bad:

Future<void> fn() async {
  await Future.wait([future]); // LINT: Avoid unnecessary collections. Try awaiting this 'Future' directly.
  await Future.any([future]); // LINT: Avoid unnecessary collections. Try awaiting this 'Future' directly.

  _array.addAll([value]); // LINT: Avoid unnecessary collections. Try using '.add' instead.
  _array.addAll({value}); // LINT: Avoid unnecessary collections. Try using '.add' instead.

  Stream.fromFutures([future]); // LINT: Avoid unnecessary collections. Try using '.fromFuture' instead.
  Stream.fromIterable([value]); // LINT: Avoid unnecessary collections. Try using '.value' instead.

  set.addAll([value]); // LINT: Avoid unnecessary collections. Try using '.add' instead.
  set.containsAll([value]); // LINT: Avoid unnecessary collections. Try using '.contains' instead.
}

✅ Good:

Future<void> fn() async {
  await future;

  _array.add(value); // Correct, 'add' instead of 'addAll'

  Stream.fromFuture(future);
  Stream.value(value);

  set.add(value);
  set.contains(value);
}