lite_ref 0.1.0

A lightweight dependency injection package with support for overriding for testing.

Overview

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

Why Lite Ref?

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

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

• Lightweight: Lite Ref has no dependencies.

• Simple: Lite Ref is simple to use and has a small API surface:

  • Create a singleton:

    final dbRef = LiteRef(create: () => 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):

    dbRef.freeze();
    

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

    final dbRef = LiteRef(create: () => Database(), cache: false);
    assert(dbRef.instance != dbRef.instance);
    

  • Create a singleton asynchronously:

    final dbRef = LiteAsyncRef(create: () 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;
    

Installation

dart pub add lite_ref

Usage

LifeRefs are lazy. They are only instantiated when you call instance or ().

import 'package:lite_ref/lite_ref.dart';


// create a singleton
final dbRef = LiteRef(create: () => Database('example-connection-string'));

// use it
// refs are also callable so you can replace dbRef.instance with dbRef()
final db = dbRef.instance;

// override for testing
dbRef.overrideWith(() => MockDatabase());

// create a transient (always new instance) by setting cache to false
final userServiceRef = LiteRef(
    create: () => UserService(database: db),
    cache: false,
  );