NestJS integration for Nodiator

Utilizes Nest's DI system to manage providers and mediator instances.

Table of contents

• Installation
• Global Configuration
• Usage
  • Exporting Mediators
  • Custom Namespaces
• Logger
• License

Installation

1npm i @nodiator/core @nodiator/nest
2# or
3yarn add @nodiator/core @nodiator/nest

Global Configuration

Nest module allows to manage multiple instances of mediators. Configuration shared by all of them can me defined via

1// app.module.ts
2import { MediatorModule } from '@nodiator/nest';
3
4@Module({
5  imports: [
6    MediatorModule.forRoot({
7      extensions: [...],
8      dynamicOptions: () => ({
9        requests: { timeout: 1000 },
10      }),
11    }),
12    CatsModule,
13  ],
14})
15export class AppModule {}

Usage

1// cats.controller.ts
2import { Mediator } from '@nodiator/nest';
3
4@Controller('cats')
5export class CatsController {
6  constructor(@InjectMediator() private readonly mediator: Mediator) {}
7
8  @Get()
9  getAllCats() {
10    return firstValueFrom(this.mediator.request(new GetAllCatsUseCase()));
11  }
12}

1// cats.module.ts
2import { MediatorModule } from '@nodiator/nest';
3
4@Module({
5  imports: [
6    MediatorModule.forFeature(CatsModule, {
7      extensions: [...],
8      dynamicOptions: () => ({
9        requests: { timeout: 1000 },
10      }),
11    }),
12  ],
13  providers: [GetAllCatsUseCaseHandler],
14  controllers: [CatsController],
15})
16export class CatsModule {}

Mediator module resolves all providers available in the scope of given module.

Exporting Mediators

Above example shows how to inject local module's mediator. To access instance from another module use

1// dogs.module.ts
2import { MediatorModule } from '@nodiator/nest';
3
4@Module({
5  imports: [MediatorModule.forFeature(DogsModule)],
6  exports: [MediatorModule], // export configured dogs mediator
7})
8export class DogsModule {}

1// cats.module.ts
2import { MediatorModule } from '@nodiator/nest';
3
4@Module({
5  imports: [
6    MediatorModule.forFeature(CatsModule),
7    DogsModule, // import dogs mediator into cats module
8  ],
9  providers: [GetAllCatsUseCaseHandler],
10  controllers: [CatsController],
11})
12export class CatsModule {}

1import { Mediator } from '@nodiator/nest';
2
3@Controller('cats')
4export class CatsController {
5  constructor(
6    @InjectMediator() private readonly catsMediator: Mediator,
7    @InjectMediator(DogsModule) private readonly dogsMediator: Mediator
8  ) {}
9
10  ...
11}

Custom Namespaces

Mediators can be provided and injected using custom string identifier. It' useful for creating abstraction from module imports dependencies.

1// cats.module.ts
2import { MediatorModule } from '@nodiator/nest';
3
4@Module({
5  imports: [
6    MediatorModule.forFeature(CatsModule, {
7      namespace: 'CATS_NAMESPACE',
8      extensions: [...],
9      dynamicOptions: () => ({
10        requests: { timeout: 1000 },
11      }),
12    }),
13  ],
14  providers: [GetAllCatsUseCaseHandler],
15  controllers: [CatsController],
16})
17export class CatsModule {}

1// cats.controller.ts
2import { Mediator } from '@nodiator/nest';
3
4@Controller('cats')
5export class CatsController {
6  constructor(@InjectMediator('CATS_NAMESPACE') private readonly mediator: Mediator) {}
7
8  @Get()
9  getAllCats() {
10    return firstValueFrom(this.mediator.request(new GetAllCatsUseCase()));
11  }
12}

Logger

The package exports logger integration if nest module is used in combination with logger extension.

1// app.module.ts
2import { LoggerExtension } from '@nodiator/extension-logger';
3import { MediatorModule, NestMediatorLogger } from '@nodiator/nest';
4
5@Module({
6  imports: [
7    MediatorModule.forRoot({
8      extensions: [new LoggerExtension({ logger: new NestMediatorLogger() })],
9    }),
10    CatsModule,
11  ],
12})
13export class AppModule {}

License

This project is licensed under the MIT License - see the LICENSE file for details.