Module

Kind: Class

Source: packages/core/injector/module.ts

Part of: Core

Module is Nest’s internal runtime representation of an application module within the dependency-injection container. It registers the module itself, ModuleRef, application configuration, injectable classes, and custom providers so dependencies can be resolved within the module scope.

Methods

Where it refuses work

• Module stops the work with RuntimeException when !this._providers.has(this._metatype).
• Module stops the work with InvalidClassException when !(type && isFunction(type) && type.prototype).
• Module stops the work with an early return when this.isCustomProvider(injectable).
• Module stops the work with an early return when (this.isTransientProvider(provider) || this.isRequestScopeProvider(provider)) && isAlread….
• Module stops the work with an early return when isString(provide) || isSymbol(provide).
• Module stops the work with an early return when this._providers.has(token).

Diagram

mermaid
graph LR
  A[Module Metadata] --> B[Module Instance]
  B --> C[Core Providers]
  C --> C1[Module Class Provider]
  C --> C2[ModuleRef]
  C --> C3[ApplicationConfig]
  B --> D[addProvider]
  B --> E[addInjectable]
  D --> F{Custom Provider?}
  F -->|No| G[Class Provider Wrapper]
  F -->|Yes| H[Factory / Value / Existing / Class Provider]
  G --> I[Provider Registry]
  H --> I
  E --> J[Injectable Registry]

Usage

ts
import { Module as RuntimeModule } from '@nestjs/core/injector/module';
import { NestContainer } from '@nestjs/core/injector/container';
import { ApplicationConfig } from '@nestjs/core/application-config';

class UsersService {
  findAll() {
    return ['Ada', 'Grace'];
  }
}

class AppModule {}

const applicationConfig = new ApplicationConfig();
const container = new NestContainer(applicationConfig);

// RuntimeModule is typically created by Nest internally during scanning.
const moduleRef = new RuntimeModule(AppModule, container);

// Register a standard class provider.
moduleRef.addProvider(UsersService);

// Register a custom value provider.
moduleRef.addProvider({
  provide: 'API_URL',
  useValue: 'https://api.example.com',
});

// Register an injectable used by framework features such as guards or pipes.
moduleRef.addInjectable(UsersService);

AI Coding Instructions

• Treat Module as an internal Nest container type; application code should usually register providers through the @Module() decorator instead.
• Use addProvider() for both class providers and custom provider objects; custom providers are detected through isCustomProvider().
• Preserve provider tokens when adding or modifying registrations, since tokens are the keys used for dependency resolution.
• Ensure new providers are associated with the correct module instance so module-scoped resolution and exports continue to work.
• Do not remove the core-provider setup path: module classes, ModuleRef, and application configuration must remain registered for Nest runtime behavior.

How it works

Module is a mutable runtime record for one module metatype within the dependency-injection container. It stores the module class, container reference, an ID, imports, exports, providers, injectables, middleware wrappers, controller wrappers, and entry-provider tokens. [packages/core/injector/module.ts:44-77]

The container creates it from a compiled module type, assigns its container token afterward, stores it in the container’s module map, and may mark it global, set its distance to Number.MAX_VALUE, and register it among global modules. [packages/core/injector/container.ts:163-184]

Relationships

• IMPORTS → EnhancerSubtype
• IMPORTS → ENTRY_PROVIDER_WATERMARK
• IMPORTS → ClassProvider
• IMPORTS → Controller
• IMPORTS → DynamicModule
• IMPORTS → ExistingProvider
• IMPORTS → FactoryProvider
• IMPORTS → Injectable
• IMPORTS → InjectionToken
• IMPORTS → NestModule
• IMPORTS → Provider
• IMPORTS → Scope
• IMPORTS → Type
• IMPORTS → ValueProvider
• IMPORTS → randomStringGenerator
• IMPORTS → isFunction
• IMPORTS → isNil
• IMPORTS → isObject
• IMPORTS → isString
• IMPORTS → isSymbol
• IMPORTS → isUndefined

Used by

4 references from 4 files. Each is a place in this repository where the symbol is actually used — go read one rather than trusting an example.

Imported by (4)

• ListenersController — packages/microservices/listeners-controller.ts:45
• TestingInjector — packages/testing/testing-injector.ts:23
• TestingInstanceLoader — packages/testing/testing-instance-loader.ts:6
• TestingModule — packages/testing/testing-module.ts:26