Node.js uses the chrome V8 engine to run javascript outside of the browser.

Install

# linux
sudo apt install nodejs -y

# Check installation success
node -v
npm -v

# update npm to latest
npm install npm@latest -g

Install the LTS version from website. Works for updating node too.

Create an npm project

Go to a project folder and run npm init. It will ask a few questions and generate a package.json file.

NPM allows to install packages 2 ways.

Locally: Runs only in the project folder. npm install modulename. Installs locally in project folder in a folder called node_modules, and adds it as a dependency into package.json's dependencies section.
Globally: Can run anywhere. Mostly in terminal: npm install -g live-server. In this case, package.json won't get updated.

Notes

If installing gives admin errors, run as sudo.
npm install installs all dependencies from package.json.
Dev dependencies are not needed for deployment so they're added to package.json's dev dependencies.

Scripts: npm run scriptname will run a bash command as specified in the package.json. eg:

"scripts" : {
    "build": "browserify script.js > bundle.js",
    "buildtest": "browserify script.js > bundle.js && live-server"
}