Demystifying Development Server Commands: "npm start" vs. "ng serve" in Angular

• Generic Command: npm start is a general-purpose command used in Node.js projects that executes a script defined in the package.json file.
• Customization: The specific script it runs depends on what's defined in the "scripts" section of package.json. By default, if no script is specified, it attempts to run node server.js.
• Flexibility: You can configure npm start to perform various tasks beyond development server startup, such as running tests, building for production, or launching a custom development environment.

ng serve

• Angular-Specific: ng serve is a command provided by the Angular CLI (Command Line Interface). It's specifically designed for starting an Angular development server.
• Features: It offers features tailored for Angular development, including:
  • Building the Angular application
  • Launching a local development server (usually on port 4200 by default)
  • Enabling live reloading: When you make changes to your code, the browser automatically refreshes to reflect the updates, streamlining the development process.
  • Proxy support: Allows you to configure a proxy to handle requests to backend APIs during development.

When to Use Which

• General Development Workflow: In most cases, you'll primarily use ng serve during your typical Angular development workflow. It provides a streamlined experience with live reloading and other features.
• Custom Start Script: If you have a more complex development setup that requires additional tasks beyond what ng serve offers, you can create a custom script in package.json and run it with npm start. For instance, you might want to run a separate backend server or perform a custom build process.

Key Points:

• In an Angular project, ng serve essentially executes a script under the hood that combines building the application and starting the development server. However, using ng serve is more convenient and provides additional benefits.
• You can still leverage npm start for custom development workflows if needed, but ng serve is the recommended approach for most Angular development scenarios.

Example Codes:

This is the typical approach for starting your Angular development server:

# Navigate to your Angular project directory
cd my-angular-project

# Start the development server
ng serve

This will compile your Angular application, bundle the assets, create a development server, and usually open your default browser at http://localhost:4200 (the default development server port) to view your application.

Custom Script with npm start:

Here's an example of a custom script in package.json that you could run with npm start:

{
  "scripts": {
    "start": "ng build && concurrently \"npm run serve\" \"npm run watch\"",
    "serve": "lite-server -c ./dist",  // Assuming you use lite-server for serving static files
    "watch": "ng serve --watch"       // Start development server with code watching
  }
}

In this example:

• npm start first runs ng build to create an optimized production build.
• The concurrently package then starts two commands simultaneously:
  • npm run serve (can be replaced with your actual serving command) serves the static files from the dist directory (assuming a production build output).
  • npm run watch (equivalent to ng serve --watch) starts the Angular development server in watch mode for automatic reloading.

• Scenario: You might prefer to have more control over the build process or integrate it into a larger build pipeline.
• Steps:
  1. Define Build Script: Create a script in your package.json that combines building and starting the server (similar to a custom npm start script).
  2. Run Script: Execute the script using npm run <script-name>.

Manual Build and Server Startup:

• Scenario: This approach is less common but could be useful for understanding the underlying steps or troubleshooting.
• Steps:
  1. Build: Run ng build to create the optimized application files.
  2. Start Server: Use a separate static file server like http-server or python -m SimpleHTTPServer to serve the built files from the output directory (usually dist).

Third-Party Development Servers:

• Scenario: You might have a preference for a different development server experience or need specific features offered by a third-party tool.
• Tools: Explore options like webpack-dev-server or browser-sync. These may require additional configuration but provide alternative development server functionalities.

Important Considerations:

• Live Reloading: While ng serve provides built-in live reloading, you might need to configure live reloading functionality manually when using alternate methods.
• Proxy Support: Setting up proxy support for backend APIs might require additional configuration steps outside of the ng serve command.
• Complexity: These alternate methods can introduce more complexity compared to the streamlined experience offered by ng serve.