Node.js – NPM Scripts

NPM Scripts allow you to run commands defined inside your package.json file.
They help automate tasks like:

• Running server

• Starting development mode

• Running tests

• Compiling code

• Cleaning files

• Building projects

Scripts make your workflow faster and more organized.

✅ 1. Where Are NPM Scripts Defined?

In your package.json file:

✅ 2. How to Run NPM Scripts

Use the command:

Example:

But for one special script:

Default Script — start

(You don’t need to type run for the start script.)

✅ 3. Common Useful NPM Scripts

1. Start the application

Run:

2. Development Mode (with Nodemon)

Run:

3. Clean build folder

Run:

4. Build project

Run:

5. Run tests

Run:

✅ 4. Using Multiple Commands in Scripts

Run two commands sequentially

Run two commands in parallel

(For Linux/Mac)

(For Windows use concurrently package)

✅ 5. Passing Arguments to Scripts

Run with arguments:

Inside Node.js:

✅ 6. Pre and Post Scripts

NPM automatically runs scripts with prefixes:

prestart → runs before start

poststart → runs after start

Example:

Run:

Order:

✅ 7. Defining Custom Scripts

You can create any script name:

Run:

✅ 8. View All Available Scripts

This shows all scripts inside package.json.

🎯 Summary