RoutesResolver

Kind: Class

Source: packages/core/router/routes-resolver.ts

Part of: Core

RoutesResolver connects discovered controllers and route metadata to the underlying HTTP adapter during application initialization. It registers controller routes, configures not-found and exception handlers, and maps framework exceptions to adapter-compatible responses.

Implements: Resolver

Methods

Where it refuses work

• RoutesResolver stops the work with an early return when versioningConfig.

Diagram

mermaid
graph LR
  A[Application bootstrap] --> B[RoutesResolver.resolve]
  B --> C[registerRouters]
  C --> D[Controller routes]
  D --> E[HTTP adapter router]

  B --> F[registerNotFoundHandler]
  F --> E

  B --> G[registerExceptionHandler]
  G --> H[mapExternalException]
  H --> E

Usage

ts
import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);

  // RoutesResolver uses this prefix while registering controller routes.
  app.setGlobalPrefix('api');

  // During initialization, Nest internally uses RoutesResolver to:
  // - discover controller routes
  // - register them with the HTTP adapter
  // - configure 404 and exception handlers
  await app.listen(3000);
}

bootstrap();

AI Coding Instructions

• Treat RoutesResolver as framework bootstrap infrastructure; application code should usually define controllers and let the framework invoke resolve().
• Preserve the registration order: controller routes should be registered before fallback not-found and exception handlers are attached.
• When adding route-related behavior, ensure global prefixes, module paths, and controller metadata are consistently applied.
• Keep adapter-specific error handling inside mapExternalException() so external HTTP adapters receive compatible error objects.
• Avoid registering catch-all routes or error middleware too early, as they can prevent resolved controller routes from being reached.

How it works

RoutesResolver

RoutesResolver is the HTTP-routing resolver created by NestApplication. During application initialization, the application invokes resolve() after middleware registration, then invokes its not-found and error-hook registration methods after initialization hooks. packages/core/nest-application.ts:190-194 packages/core/nest-application.ts:207-218

It implements the Resolver contract: route resolution plus registration of not-found and exception handlers. packages/core/router/interfaces/resolver.interface.ts:1-5

Relationships

• IMPORTS → BadRequestException
• IMPORTS → HttpException
• IMPORTS → NotFoundException
• IMPORTS → HOST_METADATA
• IMPORTS → MODULE_PATH
• IMPORTS → VERSION_METADATA
• IMPORTS → Controller
• IMPORTS → HttpServer
• IMPORTS → Type
• IMPORTS → VersionValue
• IMPORTS → Logger