Compile-Time Dependency Injection for Dart & Flutter

This package provides the annotations used to declare a compile-time dependency injection (DI) graph. It is a modern, sound null-safe port of the original inject.dart from Google.

Since this library generates code at compile time, it does not rely on runtime reflection or any kind of dynamic lookup. This ensures maximum performance and minimal build sizes for Flutter and standalone Dart applications.

Getting Started

Add inject_compile as a dependency and inject_compile_generator as a dev dependency in your pubspec.yaml file:

dependencies:
  inject_compile: ^0.9.0

dev_dependencies:
  build_runner: ^2.4.0
  inject_compile_generator: ^0.9.0

Annotations

@provide

Marks a constructor, method, or getter as providing a dependency.

• On a class constructor: Registers the class in the dependency graph so the framework knows how to instantiate it.
• On a module method/getter: Registers the return type as a dependency. The framework calls this member to obtain the instance.

@module

Marks a class as a module. Modules contain provider methods for dependencies that cannot be easily instantiated directly (such as interfaces, third-party classes, or asynchronous resources).

@injector

Marks an abstract class as the root of a dependency injection graph. The code generator creates a concrete implementation subclass (e.g., YourClass$Injector) implementing this interface.

@singleton

Combined with @provide, indicates that a dependency is instantiated only once per injector instance. All subsequent requests return the same instance.

@asynchronous

Marks a provider method returning a Future as asynchronous. The generated injector awaits the future during creation, resolving the value synchronously for any dependent classes.

@Qualifier

Differentiates multiple bindings of the same type by associating a symbol (e.g., @Qualifier(#name)) with the provider.

Next Steps

• To run the generator, refer to the inject_compile_generator package page.
• For complete samples, see the workspace examples.

Acknowledgement

Please note that all of the original code in inject.dart which these packages is heavily based on is Copyright by Google and originally licenced under a MIT Licence which has been kept. Special thanks to Matan Lurey who was the primary original author.