Creating Type-safe ClsService using custom Module

[MaheeGamage]

Can someone explain to me how to use this module that explained in README.md file
https://github.com/Papooch/nestjs-cls#type-safety-and-type-inference

export class MyClsService extends ClsService<MyClsStore> {}

@Module({
    imports: [ClsModule.forFeature()],
    providers: [{
        provide: MyClsService,
        useExisting: ClsService
    }],
    exports: [MyClsService]
})
class MyClsModule {}

I need to know after creating a custom MyClsModule how to add this module to the application.

Currently I use nestjs-cls in following manner

@Module({
  imports: [
    // Register the ClsModule,
    ClsModule.forRoot({
      middleware: {
        // automatically mount the
        // ClsMiddleware for all routes
        mount: true,
        // and use the setup method to
        // provide default store values.
        setup: (cls, req) => {
          cls.set('userId', req.headers['x-user-id']);
        },
      },
    }),
  ],
  providers: [CatService],
  controllers: [CatController],
})
export class AppModule {}

[Papooch]

You just inject MyClsService the same way you would inject ClsService. It will be typed with your MyClsStore. Of course, MyClsModule must be imported in the module where MyClsService is needed.

You do that in addition to registering it in for-root. With this method, you're basically just aliasing ClsService to MyClsService to get type inference, but the same ClsService is still used underneath.

If you want type safety even in the setup method, you can type it like so:

setup: (cls: MyClsService, req) => {
  cls.set('userId', req.headers['x-user-id']);
},

[Papooch]

An alternative to using the wrapper module is to type your ClsService injects as ClsService<MyClsStore>, and therefore:

setup: (cls: ClsService<MyClsStore>, req) => {
  cls.set('userId', req.headers['x-user-id']);
},

This way you can avoid having to create the alias class, but have to use the generic type everywhere.