Package.json Structure in NPM

From the NPM Package Manager cheat sheet · Project Setup & Initialization · verified Jul 2026

Package.json Structure

Essential fields in package.json

json

// package.json
{
  "name": "my-project",
  "version": "1.0.0",
  "description": "Project description",
  "main": "index.js",
  "type": "module",  // ES modules
  
  "scripts": {
    "start": "node index.js",
    "dev": "nodemon index.js",
    "test": "jest",
    "build": "webpack",
    "lint": "eslint ."
  },
  
  "keywords": ["nodejs", "api"],
  "author": "Your Name",
  "license": "MIT",
  
  "dependencies": {
    "express": "^4.18.0"
  },
  "devDependencies": {
    "nodemon": "^2.0.0",
    "jest": "^29.0.0"
  }
}

🟢 Essential - package.json is the project manifest

💡 Use "type": "module" for ES modules

📌 Scripts are shortcuts for common commands

⚡ "files" field controls what gets published

⚠️ Name must be lowercase and URL-safe

package.jsonconfig

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