.JSON

Introduction

package.json is the manifest of a JavaScript project or package, first defined by npm, the package manager that comes with Node.js. It names the package and its version, lists the packages it depends on, and defines scripts such as build and test that are run with npm run. Every package published to the npm registry has one, and other JavaScript tools, from Yarn and pnpm to bundlers and test runners, read it too.

Beside it, package-lock.json (or the lock file of another package manager) records the exact version of every package installed.

Structure

The file is a JSON object. A package to be published needs name and version, the version following semantic versioning. Common fields include description, license, main or exports (the files other code imports), type ("module" for ES modules), bin (commands the package installs), scripts, and the dependencies and devDependencies objects, which map package names to version ranges such as ^4.18.0.

{
  "name": "my-app",
  "version": "1.0.0",
  "type": "module",
  "scripts": {
    "start": "node server.js",
    "test": "node --test"
  },
  "dependencies": {
    "express": "^4.18.0"
  }
}

Also used for

• GeoJSON .json
• Hugging Face model config (config.json) .json
• Hugging Face tokenizer (tokenizer.json) .json
• JSON Schema .json
• JavaScript Object Notation .json
• Lottie animation .json
• Visual Studio Code settings .json

Links