nodejs-basic

Vanilla Node.js Basic Example

This example demonstrates how to use Type Config Core with vanilla Node.js (no framework).

Features

• Profile-based configuration
• Hot reload support
• Type-safe configuration classes with decorators
• No framework dependencies (pure Node.js)
• Built-in HTTP server
• Graceful shutdown handling
• Environment variable substitution

Setup

# Install dependencies
yarn install

# Run in development mode
yarn dev

Configuration

The example uses YAML configuration files located in the config/ directory:

• application.yml - Default configuration
• application-production.yml - Production profile configuration

Configuration is automatically merged based on the active profile.

Endpoints

• GET / - Welcome message with app info
• GET /config - Display bound configuration objects
• GET /raw-config - Display raw configuration (all properties)
• GET /health - Health check endpoint

Usage

# Run with development profile (default)
yarn dev

# Run with production profile
NODE_ENV=production yarn dev

# Build and run compiled version
yarn build
NODE_ENV=production node dist/index.js

Configuration Classes

ServerConfig

@ConfigurationProperties('server')
class ServerConfig {
  @ConfigProperty()
  port: number = 3000;

  @ConfigProperty()
  host: string = 'localhost';
}

DatabaseConfig

@ConfigurationProperties('database')
class DatabaseConfig {
  @ConfigProperty()
  @Required()
  host: string;

  @ConfigProperty()
  @DefaultValue(5432)
  port: number;

  @ConfigProperty()
  username: string;

  @ConfigProperty()
  password: string;
}

AppConfig

@ConfigurationProperties('app')
class AppConfig {
  @ConfigProperty()
  @DefaultValue('Node.js App')
  name: string;

  @ConfigProperty()
  @DefaultValue('1.0.0')
  version: string;

  @ConfigProperty()
  environment: string;

  @ConfigProperty()
  debug: boolean;
}

Using ConfigManager Directly

This example showcases the core ConfigManager API:

// Create and initialize
const configManager = new ConfigManager({
  profile: process.env.NODE_ENV || 'development',
  configDir: './config',
  enableHotReload: true,
});

await configManager.load();

// Register configuration classes
configManager.register(ServerConfig);
configManager.register(DatabaseConfig);
configManager.register(AppConfig);

// Bind instances
const serverConfig = configManager.bind(ServerConfig);
const dbConfig = configManager.bind(DatabaseConfig);

// Access properties
console.log(serverConfig.port); // 3000
console.log(dbConfig.host);     // localhost

// Get all config
const allConfig = configManager.getAll();

// Get active profile
const profile = configManager.getProfile();

// Listen for changes
configManager.onChange((newConfig) => {
  console.log('Config changed!', newConfig);
});

Hot Reload

When enableHotReload is true, the configuration is automatically reloaded when files in the config directory change. This is useful during development.

To test hot reload:

1. Start the server with yarn dev
2. Modify config/application.yml
3. Watch the console for the reload message
4. Visit /config to see the updated values

Environment Variables

You can use environment variable substitution in your config files:

database:
  password: ${DB_PASSWORD}

Then set the environment variable:

export DB_PASSWORD=my-secret-password
yarn dev

Graceful Shutdown

The example includes graceful shutdown handling for SIGTERM and SIGINT signals, ensuring the server closes cleanly.