nest-module-path-discovery.ts

import {Controller, Get, Module, OnApplicationBootstrap} from '@nestjs/common';
import {
  ModulesContainer,
  NestFactory,
  Reflector,
  RouterModule,
} from '@nestjs/core';

@Controller('controller-1')
class Controller1 {
  @Get('index')
  index() {}
}

@Module({
  imports: [],
  controllers: [Controller1],
  providers: [],
  exports: [],
})
class Module1 {}

@Controller('controller-2')
class Controller2 {
  @Get('index')
  index() {}
}

@Module({
  imports: [],
  controllers: [Controller2],
  providers: [],
  exports: [],
})
class Module2 {}

@Module({
  imports: [
    Module1,
    RouterModule.register([{path: 'module-1', module: Module1}]),
    Module2,
    RouterModule.register([{path: 'module-2', module: Module2}]),
  ],
  controllers: [],
  providers: [],
  exports: [],
})
export class RouteDiscoveryAppModule implements OnApplicationBootstrap {
  constructor(
    private modulesContainer: ModulesContainer,
    private reflector: Reflector
  ) {}

  onApplicationBootstrap() {
    const modules = Array.from(this.modulesContainer.values());
    const modulesWithPathPrefix = modules
      .map((module) => {
        const metadataKeys = Reflect.getMetadataKeys(module.metatype);
        const pathKey = metadataKeys.find((key) =>
          String(key).startsWith('__module_path__')
        );

        const path = pathKey
          ? this.reflector.get(pathKey, module.metatype)
          : undefined;
        return {path, module};
      })
      .filter(({path}) => Boolean(path));

    console.log(modulesWithPathPrefix);
  }
}

Promise.resolve().then(async () => {
  const app = await NestFactory.create(RouteDiscoveryAppModule);
  app.listen(3001);
});