Yarn

YARN 🧶

YARN is a fast, reliable, and secure dependency management tool for Node.js. It was developed by Facebook in 2016 as an alternative to npm (Node Package Manager).

Architecture and Concepts 🏗️

YARN's architecture is designed for efficiency and reliability:

• 📁 Workspace: The root directory of your project

• 📄 package.json: Defines project dependencies and scripts

• 🔒 yarn.lock: Ensures consistent installs across machines

• 📦 node_modules: Directory where packages are installed

• 🌐 Registry: Default is npm registry, but can be changed

Key Concepts:

• 🔄 Offline Mode: Install packages without internet connection

• 🚀 Parallel Installation: Faster package installations

• 🔍 Flat Mode: Resolves version conflicts efficiently

• 🔐 Checksums: Verifies integrity of installed packages

YARN Architecture Diagram 📊

Common YARN Commands 🖥️

Installation:

npm install -g yarn

Initialize a new project:

yarn init

Add a dependency:

yarn add [package-name]
yarn add [package-name]@[version]
yarn add [package-name] --dev

Remove a dependency:

yarn remove [package-name]

Install all dependencies:

yarn install

Run a script:

yarn run [script-name]

Upgrade packages:

yarn upgrade
yarn upgrade [package-name]
yarn upgrade [package-name]@[version]

Code Snippets 💻

Example package.json:

{
  "name": "my-project",
  "version": "1.0.0",
  "dependencies": {
    "express": "^4.17.1"
  },
  "devDependencies": {
    "jest": "^27.0.6"
  },
  "scripts": {
    "start": "node index.js",
    "test": "jest"
  }
}

Example JavaScript file (index.js):

const express = require('express');
const app = express();
const port = 3000;

app.get('/', (req, res) => {
  res.send('Hello World!');
});

app.listen(port, () => {
  console.log(`Example app listening at <http://localhost>:${port}`);
});

Running the application:

yarn start

Output:

Example app listening at <http://localhost:3000>

Deployment Commands 🚀

Deployment commands may vary depending on your hosting platform. Here are some general examples:

Build for production:

yarn build

Run tests before deployment:

yarn test

Start in production mode:

yarn start:prod

Remember to add these scripts to your package.json file:

{
  "scripts": {
    "build": "your-build-command",
    "test": "jest",
    "start:prod": "NODE_ENV=production node index.js"
  }
}

Conclusion 🎉

YARN is a powerful and efficient package manager for Node.js projects. Its architecture and features make it a popular choice for many developers. By understanding its concepts and commands, you can streamline your development process and manage dependencies more effectively.