Real projects use many libraries. `npm` is the tool that downloads and manages them. Learn `package.json`, `npm init`, and `npm install express` so your project is organised like a real one.
About 2 min of reading
You never commit node_modules to version control. It can contain thousands of files.
Instead, package.json records the versions you need, and anyone cloning your project runs npm install to recreate the folder. A file called .gitignore tells git to skip node_modules:
node_modules/This keeps your repository small and lets your app be rebuilt anywhere.
In a new folder run:
npm init -y
npm install expressThis creates **package.json*: a small file that records your project's name, version, and dependencies. It looks like:
{
"name": "my-app",
"version": "1.0.0",
"dependencies": {
"express": "^4.18.2"
}
}The node_modules folder now contains the Express code. You never edit it, you only use it with require.
package.json is the identity card of your project. Every line matters.
name: the project's identifier.version: follows semantic versioning: major.minor.patch.dependencies: the libraries your app needs to run.scripts: shortcuts for commands, like "start": "node server.js".{
"scripts": {
"start": "node server.js"
}
}Now npm start is the same as typing node server.js. Small shortcuts add up over a big project.
Each one is defined here on this site. Open the entry for the full definition and the other words it points at.