Overview

Lite Ref is a lightweight dependency injection library for Dart and Flutter.

Installation

dart pub add lite_ref

Why Lite Ref?

• Fast: Doesn't use hashmaps to store instances so it's faster than all other DI libraries.

• Safe: Uses top level variables so it's impossible to get a NOT_FOUND error.

• Lightweight: Has no dependencies.

• Simple: Easy to learn with a small API surface:

  • Create a singleton:

    final dbRef = Ref.singleton(() => Database());
    
    assert(dbRef.instance == dbRef.instance);
    

  • Use it:

    final db = dbRef.instance; // or dbRef()
    

  • Override it (for testing):

    dbRef.overrideWith(() => MockDatabase());
    

  • Freeze it (disable overriding):

    // overrideWith is marked as @visibleForTesting so this isn't really necessary.
    dbRef.freeze();
    

  • Create a transient instance (always return new instance):

    final dbRef = Ref.transient(() => Database());
    
    assert(dbRef.instance != dbRef.instance);
    

  • Create a singleton asynchronously:

    final dbRef = Ref.asyncSingleton(() async => await Database.init());
    

  • Use it:

    final db = await dbRef.instance;
    

  • Use it synchronously:

    // only use this if you know the instance is already created
    final db = dbRef.assertInstance;
    

Click here for a flutter example with testing.