JS Tutorial

JavaScript Arrays

A JavaScript Array is a special type of object used to store multiple values in a single variable. Arrays are zero-indexed and dynamic (can grow or shrink).

📌 Array Syntax

let fruits = ["Apple", "Banana", "Mango"];
let numbers = [10, 20, 30, 40];
let mixed = [1, "hello", true];
  

🧪 Try It Yourself:

Open your browser console and try this code:

let colors = ["Red", "Green", "Blue"];
console.log(colors[0]);       // Red
console.log(colors.length);   // 3
colors.push("Yellow");        // Add new item
console.log(colors);          // ["Red", "Green", "Blue", "Yellow"]
colors.pop();                 // Remove last item
  

🧰 Common Array Methods

• push() – Adds item to end
• pop() – Removes item from end
• shift() – Removes item from start
• unshift() – Adds item to start
• slice(start, end) – Extracts a portion
• splice(start, deleteCount) – Removes or replaces elements
• indexOf() – Finds index of item
• includes() – Checks if item exists
• join() – Converts to string

🔧 Live Example: Dynamic Array Display

🧠 Array Iteration

let numbers = [10, 20, 30];

numbers.forEach(function(num) {
  console.log(num);
});

// Using arrow function
numbers.forEach(num => console.log(num));
  

💡 Tips

• Arrays are objects in JavaScript — typeof [] === "object"
• Use Array.isArray() to check if a variable is an array.
• Use modern methods like map(), filter(), and reduce() for powerful array operations.