npm scripts let you define shortcuts for common commands in package.json. Run them with npm run <script-name>. Built-in scripts like start and test can be run without the run keyword.
npx executes a package without installing it globally, useful for one-time tools like project scaffolding.
// package.json — scripts section
{
"scripts": {
"start": "node src/index.js",
"dev": "nodemon src/index.js --watch src",
"build": "tsc -p tsconfig.json",
"test": "jest --coverage",
"lint": "eslint src/**/*.js",
"format": "prettier --write src/**/*.js",
"db:seed": "node scripts/seed.js",
"postinstall": "echo 'Dependencies installed!'"
}
}
# Run scripts:
npm start # node src/index.js
npm run dev # nodemon ...
npm test # jest --coverage
npm run lint
# npx — run without global install:
npx create-react-app my-app
npx cowsay "Hello npm!"
# Check for outdated packages:
npm outdated
# Update a package:
npm update express
# See details about a package:
npm info lodash version