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Router module

Hint

This chapter is only relevant to HTTP-based applications.

In an HTTP application (for example, REST API), the route path for a handler is determined by concatenating the (optional) prefix declared for the controller (inside the @Controller decorator), and any path specified in the method's decorator (e.g, @Get('users')). You can learn more about that in this section. Additionally, you can define a global prefix for all routes registered in your application, or enable versioning.

Also, there are edge-cases when defining a prefix at a module-level (and so for all controllers registered inside that module) may come in handy. For example, imagine a REST application that exposes several different endpoints being used by a specific portion of your application called "Dashboard". In such a case, instead of repeating the /dashboard prefix within each controller, you could use a utility RouterModule module, as follows:

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@Module({
  imports: [
    DashboardModule,
    RouterModule.register([
      {
        path: 'dashboard',
        module: DashboardModule,
      },
    ]),
  ],
})
export class AppModule {}

Hint

The RouterModule class is exported from the @nestjs/core package.

In addition, you can define hierarchical structures. This means each module can have children modules. The children modules will inherit their parent's prefix. In the following example, we'll register the AdminModule as a parent module of DashboardModule and MetricsModule.

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RouterModule.register([
  {
    path: 'admin',
    module: AdminModule,
    children: [
      {
        path: 'dashboard',
        module: DashboardModule,
      },
      {
        path: 'metrics',
        module: MetricsModule,
      },
    ],
  },
]);

Hint

This feature should be used very carefully, as overusing it can make code difficult to maintain over time.

In the example above, any controller registered inside the DashboardModule will have an extra /admin/dashboard prefix (as the module concatenates paths from top to bottom - recursively - parent to children). Likewise, each controller defined inside the MetricsModule will have an additional module-level prefix /admin/metrics.