• A command-line tool to share and control modules (or packages) of JavaScript code written for use with Node.js.
• When starting a new project, npm generates a package.json file.
• npm saves packages in a node_modules folder.

package.json

• The center of any Node.js project or npm package.
• Located in root level of project.
• Stores information about your project.
• Consists of a single JSON object where information is stored in key-value pairs.

• Only two required fields - name and version

  • But it’s good practice to provide additional information about your project.

Semantic versioning

"package": "MAJOR.MINOR.PATCH"

• MAJOR version

  • should increment when you make incompatible API changes.
  • add changes that won’t work with earlier versions.

• MINOR version

  • should increment when you add functionality in a backwards-compatible manner.
  • add new features but neither of them break what worked before.

• PATCH version

  • should increment when you make backwards-compatible bug fixes.

Allow version upgrade

• To allow the latest PATCH updates, prefix it with the tilde (~).
• e.g. Allow to update to any 2.10.x version.

"package": "~2.10.4"

• To allow the latest MINOR updates and PATCH updates, prefix it with the caret (^).
• e.g. Allow to update to any 2.x.x version.

"package": "^2.10.4"

Remove packages

npm uninstall package