Code generation

Core library
Code generation
- Setting up code generation

When we create a service that depends on several others, we usually pass these dependencies through the constructor. This is what is usually called dependency injection:

class MyService implements Initializable, Disposable {
  MyService(this.dependencyA, this.dependencyB);

  final DependencyA dependencyA;
  final DependencyB dependencyB;

  Future<void> initialize() async {
    // Perform initialization here
  }

  Future<void> dispose() async {
    // Perform disposal here
  }
}

To register an implementation for it without using code generation, we would write the following code:

services.addSingletonFactory(
  (sp) => MyService(
    sp.getRequired<DependencyA>(),
    sp.getRequired<DependencyB>(),
  ),
);

services.addAlias<Initializable, MyService>();
services.addAlias<Disposable, MyService>();

Not only did we have to manually pass all the dependencies to the constructor, but we also had to register aliases for its interfaces.

Of course, in order not to force developers to write a lot of boilerplate code, dino provides the ability to use code generation.

Setting up code generation

To use code generation, you need to add a dev dependency to your project:

dev_dependencies:
  dino_generator:
  build_runner:

Now we can annotate our services with @service annotation:

import 'package:dino/dino.dart';

@service
class MyService implements Initializable, Disposable {
  MyService(this.dependencyA, this.dependencyB);

  final DependencyA dependencyA;
  final DependencyB dependencyB;

  Future<void> initialize() async {
    // Perform initialization here
  }

  Future<void> dispose() async {
    // Perform disposal here
  }
}

If you run pub run build_runner build now, you will see that the generator has created a file called my_service.g.dart in the same directory as your service. This file contains the extension methods that we wrote manually before. Now you can use them in your code:

services.addMyService(ServiceLifetime.singleton);

You can also use the @Service annotation to provide the lifetime of the service. In this case, you can omit the lifetime parameter in the addMyService.

dino/docs/code-generation.md

Code generation

Setting up code generation