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JavaScript

JavaScript is the programming language of the web, enabling interactive and dynamic content in browsers and powering server-side applications with Node.js.

What You'll Learn​

Comprehensive JavaScript development from modern ES6+ features to testing and build tools.

Fundamentals​

Master modern JavaScript (ES6+) syntax and core concepts.

Topics covered:

  • ES6+ features (arrow functions, destructuring, modules)
  • Async programming (promises, async/await)
  • Modern JavaScript best practices
  • Browser and Node.js APIs

Testing​

Write reliable, maintainable tests for your JavaScript applications.

Topics covered:

  • Jest testing framework (setup and examples)
  • Testing framework comparisons
  • Unit and integration testing
  • Best practices and patterns

Quick Start​

Installation​

JavaScript runs in all modern browsers. For Node.js development:

# Install Node.js (includes npm)
# Download from: https://nodejs.org/

# Verify installation
node --version
npm --version

Your First JavaScript Program​

Browser:

<!DOCTYPE html>
<html>
<head>
  <title>Hello JavaScript</title>
</head>
<body>
  <h1 id="greeting">Hello</h1>

  <script>
    document.getElementById('greeting').textContent = 'Hello, JavaScript!';
    console.log('JavaScript is running!');
  </script>
</body>
</html>

Node.js:

// hello.js
console.log('Hello, JavaScript!');

// Run with: node hello.js

Why JavaScript?​

Strengths​

  • Universal - Runs in every browser and on servers (Node.js)
  • Versatile - Frontend, backend, mobile, desktop applications
  • Huge Ecosystem - npm has millions of packages
  • Active Community - Largest developer community
  • Modern Features - Continuously evolving (ES6+, ES2020+)
  • Async by Nature - Built for handling asynchronous operations
  • Easy to Learn - Low barrier to entry, forgiving syntax

Use Cases​

  • Web applications (React, Vue, Angular)
  • Server-side applications (Node.js, Express, Nest.js)
  • Mobile apps (React Native, Ionic)
  • Desktop apps (Electron)
  • Real-time applications (WebSockets, Socket.io)
  • APIs and microservices
  • Browser extensions
  • Game development

Learning Path​

  1. Start with Fundamentals - Learn modern JavaScript syntax and core concepts
  2. Learn Testing - Write tests with Jest
  3. Explore Frameworks - React, Vue, or AngularJS for frontend
  4. Build APIs - Express.js or Nest.js for backend

JavaScript Ecosystem​

Frontend Frameworks​

  • React - Component-based UI library
  • Vue - Progressive framework
  • Angular - Full-featured framework
  • Svelte - Compiled framework

Backend/Runtime​

  • Node.js - JavaScript runtime built on V8
  • Deno - Secure TypeScript/JavaScript runtime
  • Bun - Fast all-in-one JavaScript runtime

Build Tools​

  • Vite - Next-generation frontend tooling
  • Webpack - Module bundler
  • esbuild - Extremely fast bundler
  • Rollup - Module bundler for libraries

Package Managers​

  • npm - Default Node.js package manager
  • yarn - Fast, reliable package manager
  • pnpm - Fast, disk-efficient package manager

Modern JavaScript (ES6+)​

JavaScript has evolved significantly with yearly updates:

ES6 (2015) - Major Update​

  • Arrow functions
  • Classes
  • Modules (import/export)
  • Template literals
  • Destructuring
  • Promises
  • let/const

ES2016-ES2023​

  • Async/await (ES2017)
  • Optional chaining ?. (ES2020)
  • Nullish coalescing ?? (ES2020)
  • Array methods (flat, flatMap)
  • Object methods (entries, values)
  • Top-level await (ES2022)

Start your JavaScript journey today!