We have been using this injector in all our projects for quite a while now. It does not replace a complex dependency injection framework like Dagger, but it provides the basics that most apps need. Feature requests are welcomed!

Internally the injector is a singleton that stores instances and builders in a Map.

Use registerDependency<Type>() to register the dependency. Never ever try to register or get dependencies without the generic type! Dart allows it, but we don't ;)

All instances are lazy loaded, meaning that at the time you request the dependency the instance is created. Therefore you are registering a builder function that hands you a injector that you HAVE TO USE when getting child dependencies.

Get your dependency using getDependency<Type>().

A simple usage example:

// Register a dependency (Every time a new instance)
injector.registerDependency<Car>((injector) {
      var engine = injector.getDependency<Engine>();
      var fuel = injector.getDependency<Fuel>();
      var driver = injector.getDependency<Driver>();
      
      return CarImpl(engine,fuel,driver);
    });
    
// Register a singleton
 injector.registerSingleton<Car>((injector) {
          var engine = injector.getDependency<Engine>();
          var fuel = injector.getDependency<Fuel>();
          var driver = injector.getDependency<Driver>();
          
          return CarImpl(engine,fuel,driver);
        });
    
// Register your dependencies / singletons in the  __main.dart__ file

Please file feature requests and bugs at the issue tracker.