npm-quick-tutorial

NodeJs npm quick tutorial - in 5 minutes.

Into

Npm official homepage: https://www.npmjs.com/

"npm is the package manager for JavaScript. Find, share, and reuse packages of code from hundreds of thousands of developers — and assemble them in powerful new ways." [npmjs.com]

Official getting started guide: https://docs.npmjs.com/getting-started/what-is-npm

2016-10 New package manager (alternative to npm)

There is new package manager called yarn: https://yarnpkg.com/

It's compatible with npm but it comes with number of interesting features like - better performance, offline packages caching, dependencies lock (similar to shrinkwrap), etc. I would recomend to use this tool.

Most useful commands

npm -v gets your version of npm

npm init created basic package.json - interactive process

npm install (npm install / npm i) install dependencies from package.json / npm-shrinkwrap.json (if locked)

npm install PACKAGE_NAME installs new package (or change version with npm install somepackage@1.1.0)

• -g install globally
• --save saves package into dependenvies (package.json)
• --save-dev saves package into development dependencies (package.json)

npm update (npm update --save / --save-dev) updates dependencies

npm prune removes unnecessary dependencies (not licted in packages.json)

npm shrinkwrap lock dependencies (npm install will be installing versions from npm-shrinkwrap.json file)

npm start starts application (start script entry must be defined in packages.json)

npm test run tests (tests script entry must be defined in packages.json)

npm run CUSTOM_ENTRY_NAME runs custom command defined in packages.json (scripts entry)

npm dedupe reduces dependencies duplication by moving deps up on the tree

npm publish publishes application into npmjs server

More commands in official documentation https://docs.npmjs.com/

How to pass parameters inside scripts function

By passing params with -/-- params are available only in declaration of command in package.json.

Example package.json:

...
"scripts": {
  "somescript": "npm run otherscript"
}
...

If we want to pass parameters into otherscript through somescript we would need to use command -- before actual parameter:

• npm run somescript -- --parameter=value

With "double --" parameters are passed directly into nested function.