ESenav

JavaScript Mastery 2025

Learn modern JavaScript with interactive code examples, step-by-step explanations, and real-world projects.

1 of 14 lessons (7% complete) 2h 15m total

Getting Started with JavaScript

// Hello World in JavaScript
console.log("Hello, JavaScript!");

// Node.js installation
npm init -y
npm install typescript ts-node

Start your JavaScript journey with simple examples. This setup prepares your environment with Node.js, TypeScript, and necessary tools.

  • ES2021+

    Modern JavaScript features like top-level await

  • TypeScript Ready

    Type annotations and interfaces

  • Node.js 20

    Server-side JavaScript execution

Master JavaScript Fundamentals

  • 1. Variables and Scope

    // Different declaration types
    const pi = 3.14;
    let counter = 0;
    var year = 2024;
    
    // Scope comparison
    if (true) {
        let blockScoped = true;
    }

    Understand variable declaration patterns and scope differences between var, let, and const.

  • 2. Functional Programming

    // Higher-order functions
    const numbers = [1, 2, 3];
    numbers.map(x => x * 2);
    
    // Pure function example
    function add(x, y) {
        return x + y;
    }
    
    // Immediately-invoked function
    const area = (function((x, y) { return x * y; })(3, 5));

    Use higher-order functions and pure functions for better code organization and maintainability.

Build a Calculator

Final Application Features

  • ✅ Basic arithmetic operations
  • ✅ Keyboard input support
  • ✅ Memory storage
  • ✅ Customizable UI themes

Project Preview

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🔗 Project Code on GitHub

You've Learned!

  • 📦 Variable declaration patterns
  • 🔄 Function concepts
  • 🔒 Scope and closures
  • 🔁 Iteration patterns