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Level 5: Kickoff — Start the Server

Practice spinning up an Express app and verifying that you can access it from a client. This level should feel quick—you only need a root route and confidence that the server responds.

Understanding Node.js Runtime and Development Tools

Before starting your server, it’s helpful to understand the tools you’ll use to run your Node.js application:

node vs nodemon

node is the Node.js runtime itself—the program that executes JavaScript files:

• Run a file directly: node src/index.js
• Starts your server once
• If you make code changes, you must manually stop and restart the server (Ctrl+C, then run again)

nodemon is a development tool that wraps node with automatic restarts:

• Watches your files for changes
• Automatically restarts the server when you save changes
• Saves time during development—no need to manually restart after each edit
• Not for production—use node instead

Example:

# Using node directly (manual restart required)
node src/index.js

# Using nodemon (auto-restart on file changes)
nodemon src/index.js

npm run start vs npm run dev

These are npm scripts defined in your package.json. The difference depends on what each script does:

npm run start (Production/Standard):

• Typically runs your server with node (production mode)
• Example: "start": "node src/index.js"
• Server runs once; requires manual restart for changes
• Use when you want stable, one-time execution

npm run dev (Development):

• Typically runs your server with nodemon (development mode)
• Example: "dev": "nodemon src/index.js"
• Server auto-restarts on file changes
• Use during development for faster iteration

Why have both?

• Development: Use npm run dev for auto-restart convenience while coding
• Production: Use npm run start for stable, predictable server execution
• Team Consistency: Everyone uses the same commands regardless of their setup

Check your package.json:

{
  "scripts": {
    "start": "node src/index.js",
    "dev": "nodemon src/index.js"
  }
}

Quick Start

1. Start your server:

   npm run dev
   

2. Verify it’s running:
   • Look for a message like “Server running on http://localhost:3000”
   • Try accessing http://localhost:3000 in your browser
3. Test auto-restart (if using dev):
   • Make a small change to your code (e.g., change a message)
   • Save the file
   • Watch the terminal—nodemon should automatically restart the server
4. Check your root route:
   • Visit http://localhost:3000 in your browser
   • You should see a JSON response or your configured response