Erstellen eines leichtgewichtigen Dependency-Injection-Containers

type Token<T> = { readonly id: symbol };
 
function createToken<T>(description: string): Token<T> {
  return { id: Symbol(description) };
}
 
class ServiceContainer {
  private services = new Map<symbol, unknown>();
 
  register<T>(token: Token<T>, instance: T): void {
    this.services.set(token.id, instance);
  }
 
  resolve<T>(token: Token<T>): T {
    const service = this.services.get(token.id);
    if (!service) {
      throw new Error(`Service not registered for token: ${token.id.toString()}`);
    }
    return service as T;
  }
}
 
interface Logger {
  log(msg: string): void;
}
 
const LoggerToken = createToken<Logger>("Logger");
const container = new ServiceContainer();
container.register(LoggerToken, { log: (msg) => console.log(msg) });
const logger = container.resolve(LoggerToken);
logger.log("DI Container initialized");