\begin{figure}[H]
  \begin{lstlisting}[language=JavaScript]
export abstract class IChildService {
  // ...
}

@Injectable(IChildService)
export class ChildService implements IChildService {
  // ...
}

@Injectable()
export class ParentService {
  private childService: IChildService;

  constructor(
    childService: IChildService
  ) {
    this.childService = IChildService;
  }

  // ...
}

@Module({
  providers: [
    ChildService,
    ParentService
  ],
  exports: [
    ParentService
  ]
})
export class ParentModule {}
  \end{lstlisting}

  \centering
  \includegraphics{nestjs1}
  \caption{Exemple d'injection de dépendances avec NestJS}
  \label{nestjs1}
\end{figure}