The DIContainer singleton provides low-level access to the dependency injection system. Most applications won't need this directly, but it is useful for testing, dynamic providers, and framework extensions.

Getting an Instance

import { DIContainer } from "nestelia";

const service = await DIContainer.get(UserService, UserModule);

Registering Providers

DIContainer.register([
  UserService,
  { provide: "CONFIG", useValue: { port: 3000 } },
], MyModuleClass);

Registering Controllers

DIContainer.registerControllers([UserController, AdminController], MyModuleClass);

Clearing the Container

Useful for test isolation — removes all registered modules and providers:

import { beforeEach } from "bun:test";
import { DIContainer } from "nestelia";

beforeEach(() => {
  DIContainer.clear();
});

Module Management

// Add a module
const moduleRef = DIContainer.addModule(MyModule, "MyModule");

// Get a module by key
const moduleRef = DIContainer.getModuleByKey("MyModule");

// Get all modules
const modules = DIContainer.getModules();

Request Scope

The container uses AsyncLocalStorage to manage request-scoped providers. When a request arrives:

1. Container.runInRequestContext() creates a new context
2. REQUEST-scoped providers get a fresh instance for that context
3. The context is cleaned up after the response

@Injectable({ scope: Scope.REQUEST })
class RequestLogger {
  private requestId = crypto.randomUUID();

  log(message: string) {
    console.log(`[${this.requestId}] ${message}`);
  }
}

Module Key Resolution

Providers are scoped to modules. When calling DIContainer.get(), pass the module class to look up providers within a specific module:

const service = await DIContainer.get(UserService, UserModule);

If omitted, the container searches all modules.

Global Modules

// Mark a module as global so its providers are accessible everywhere
const moduleRef = DIContainer.addModule(ConfigModule, "ConfigModule");
DIContainer.addGlobalModule(moduleRef);
DIContainer.bindGlobalScope();