flutter_unused_code 0.1.0

Finds dead code in Dart and Flutter projects - unused files, declarations, public members and widgets - using a resolved reference graph.

example/README.md

Example

A small Dart app with some dead code, and what unused_code reports for it.

Project

todo_app/
├── pubspec.yaml
└── lib/
    ├── main.dart
    ├── legacy/old_sync.dart
    └── src/
        ├── todo.dart
        └── todo_store.dart

pubspec.yaml (publish_to: none and lib/main.dart make it an app, so lib/main.dart is the entry point):

name: todo_app
publish_to: none
environment:
  sdk: ^3.11.0

lib/main.dart:

import 'src/todo.dart';
import 'src/todo_store.dart';

void main() {
  final store = TodoStore()..add(Todo('Buy milk'));
  print(store.items.length);
}

lib/src/todo.dart:

class Todo {
  Todo(this.title, {this.priority = 0});

  final String title;
  final int priority;

  Todo copyWith({String? title}) => Todo(title ?? this.title);

  String get shortTitle =>
      title.length > 10 ? '${title.substring(0, 10)}...' : title;
}

String formatTodo(Todo todo) => '- ${todo.title}';

lib/src/todo_store.dart:

import 'todo.dart';

class TodoStore {
  final List<Todo> items = [];

  void add(Todo todo) => items.add(todo);

  void clearCompleted() {
    items.clear();
  }
}

lib/legacy/old_sync.dart (nothing imports it):

import '../src/todo.dart';

Future<void> syncTodos(List<Todo> todos) async {
  for (final todo in todos) {
    print(todo.title);
  }
}

Run it

dart pub global activate flutter_unused_code
cd todo_app
dart pub get          # the analyzer needs resolved packages
unused_code --no-color

lib/legacy/old_sync.dart
  unused file (8 lines)

lib/src/todo.dart
  5:13     unused field Todo.priority (1 line)
  9:14     unused getter Todo.shortTitle (2 lines)
  13:8     unused function formatTodo (1 line)

lib/src/todo_store.dart
  8:8      unused method TodoStore.clearCompleted (3 lines)

1 unused file, 1 unused declaration (0 widgets), 3 unused members - ~15 removable lines
Analyzed 4 files (app mode) in 1.8s.

copyWith is not reported because it is a known convention. Todo.priority is reported because it is only ever set through this.priority, never read.

In CI

--fail-on-unused turns the report into a gate (exit code 1 when anything is unused):

unused_code --format github --fail-on-unused

Configure

unused_code.yaml next to pubspec.yaml:

unused_code:
  exclude:
    - lib/legacy/**
  ignore_names:
    - ^Todo\.priority$

With it, the unused file and Todo.priority are no longer reported:

lib/src/todo.dart
  9:14     unused getter Todo.shortTitle (2 lines)
  13:8     unused function formatTodo (1 line)

lib/src/todo_store.dart
  8:8      unused method TodoStore.clearCompleted (3 lines)

0 unused files, 1 unused declaration (0 widgets), 2 unused members - ~6 removable lines