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NodeJS

npm Commands

This command will install the package-name & add to the package.json

npm install package-name

This command will install the latest version of given package-name

npm install package-name@latest

This command will install the specific version of given package-name

npm install package-name@version
npm install jest@18.1.0

This command will remove or uninstall the package-name from node_modules & package.json

npm uninstall package-name

This command is to get a list of all available npm commands.

npm help

This command will print all top-level installed packages and their dependencies in a tree structure.

npm list

This command will show all the information about the given package-name 

npm show package-name

This command will show all outdated packages in the current folder.

npm outdated

This command will show all globally installed outdated packages.

npm outdated -g

This command will update the outdated packages in the current folder

npm update

This command will update the globally installed outdated packages

npm update -g

This command will update the specific packages in the current folder

npm update jest

npm run scripts

This command will provide information on how npm handles the "scripts" field

npm help npm-scripts

Aliases

npm uses a number of aliases for common commands:

i is an alias for install

un is an alias for uninstall

up is an alias for update

ls is an alias for list

Package.JSON

Run the command npm init to create the file while answering some questions about your project.

Run the command npm init -y to create the file with default values without a need to answer any question.

This file:

  • Contains meta-data about your project
  • Manages dependencies of your project
  • Contains scripts that help in generating builds, running tests and some other stuff

All package.json requires:

  • "name" - It must be all in lower case and contain no spaces
  • "version" - This uses semantic versioning.

Run the command npm install to install dependencies from an existing project using Package.JSON

Adding dependencies to Package.JSON

npm install packagename --save //install as devDependency

Note: As of npm 5.0.0, installed modules are added as a dependency by default, so the --save option is no longer needed. 

npm install -D packagename //install as a dependency
npm help install //to check the help for npm install command

Installing npm packages locally or globally

npm install packagename //installs locally. The command will be available to run from the folder where it is installed.

npm install -g packagename //installs globally.The command will be available to run from anywhere.

npm packages can be installed locally or globally.

Package-lock.JSON

  • Automatically generated for any operations where npm modifies either the node_modules tree or package.json.
  • As the package-lock specifies a version, location and integrity hash for every module and each of its dependencies, the install it creates will be the same, every single time.

References:

https://medium.com/beginners-guide-to-mobile-web-development/why-package-json-npm-basics-cab3e8cd150

https://medium.com/coinmonks/everything-you-wanted-to-know-about-package-lock-json-b81911aa8ab8

Semantic Versioning (SemVer)

Major.Minor.Patch (4.5.0)

  • Major: Breaking Changes
  • Minor: Backward Compatible
  • Patch: Bug Fixes

Symbols used in SemVer:

~ means update can install the most recent patch version (e.g. ~4.5.0) - matches any 4.5.x version.

^ means update can install most recent minor version (e.g. ^4.5.0) - matches any 4.x.y version.

Common Issues

Issue:

Error: Cannot find module '../lib/utils/unsupported.js'

Solution:

Uninstall node: brew uninstall --force node

Install it again: brew install node

If the above solution doesn't work, check out: https://gist.github.com/DanHerbert/9520689

OR run brew uninstall --force node then visit https://nodejs.org/en/ and download the LTS version and install and the error will be gone.

Issue:

npm throws error while trying to install any package globally without using sudo

Solution:

Check out:

https://www.competa.com/blog/how-to-run-npm-without-sudo/

https://www.competa.com/blog/use-nvm-for-fun-and-profit-and-to-run-npm-without-sudo/