Global modules in NestJS - Mini Project: Build & Apply

Creating and Using a Global Module in NestJS

📖 Scenario: You are building a NestJS application that needs a shared service accessible across multiple modules without importing it repeatedly.

🎯 Goal: Create a global module that provides a ConfigService accessible anywhere in the app without importing the module multiple times.

📋 What You'll Learn

Create a module named ConfigModule that is global

Create a service named ConfigService inside ConfigModule

Make sure ConfigService is provided and exported by ConfigModule

Use the @Global() decorator to make ConfigModule global

💡 Why This Matters

🌍 Real World

Global modules in NestJS help share common services like configuration or logging across the whole app without repeated imports.

💼 Career

Understanding global modules is important for building scalable and maintainable backend applications with NestJS.

1

Create the ConfigService class

Create a class called ConfigService with a method get() that returns the string 'Config value'.

NestJS

# Create the ConfigService class with a get() method
# Your code here

Need a hint?

Define a class with a method that returns a fixed string.

2

Create the ConfigModule and provide ConfigService

Create a module called ConfigModule that provides and exports ConfigService. Use the @Module() decorator with providers and exports arrays containing ConfigService.

NestJS

export class ConfigService {
  get() {
    return 'Config value';
  }
}

// Create ConfigModule with providers and exports
# Your code here

Need a hint?

Use @Module decorator with providers and exports arrays.

3

Make ConfigModule global

Add the @Global() decorator above the @Module() decorator in ConfigModule to make it global.

NestJS

import { Module } from '@nestjs/common';

export class ConfigService {
  get() {
    return 'Config value';
  }
}

// Add @Global decorator here
@Module({
  providers: [ConfigService],
  exports: [ConfigService],
})
export class ConfigModule {}

Need a hint?

Import Global from @nestjs/common and add @Global() above @Module().

4

Import ConfigModule in AppModule without re-importing ConfigService

Create an AppModule that imports only ConfigModule. Do not provide ConfigService again. Use @Module() decorator with imports array containing ConfigModule.

NestJS

import { Module, Global } from '@nestjs/common';

export class ConfigService {
  get() {
    return 'Config value';
  }
}

@Global()
@Module({
  providers: [ConfigService],
  exports: [ConfigService],
})
export class ConfigModule {}

// Create AppModule importing ConfigModule
# Your code here

Need a hint?

Define AppModule with @Module decorator importing ConfigModule.