JS Tutorial

JavaScript Array Methods

Array methods help you manipulate arrays easily — adding, removing, searching, transforming, and more. Let’s look at the most commonly used ones with examples.

🛠️ Basic Array Methods

• push() – Adds to the end
• pop() – Removes from the end
• shift() – Removes from the beginning
• unshift() – Adds to the beginning

let fruits = ["Apple", "Banana"];
fruits.push("Mango");    // ["Apple", "Banana", "Mango"]
fruits.pop();            // ["Apple", "Banana"]
fruits.shift();          // ["Banana"]
fruits.unshift("Grapes");// ["Grapes", "Banana"]
  

🔍 Searching Methods

• indexOf() – Finds index of an item
• includes() – Checks if item exists

let colors = ["Red", "Blue", "Green"];
colors.indexOf("Blue");     // 1
colors.includes("Green");   // true
  

✂️ Extracting & Modifying

• slice(start, end) – Extracts a section
• splice(start, deleteCount, item1, ...) – Adds/removes elements

let nums = [10, 20, 30, 40, 50];
let sliced = nums.slice(1, 4);    // [20, 30, 40]

nums.splice(2, 1, 99);            // [10, 20, 99, 40, 50]
  

🔄 Transforming Arrays

• map() – Transforms each item
• filter() – Filters based on condition
• reduce() – Reduces to a single value

let numbers = [1, 2, 3, 4];

let doubled = numbers.map(n => n * 2);    // [2, 4, 6, 8]
let evens = numbers.filter(n => n % 2 === 0); // [2, 4]
let sum = numbers.reduce((a, b) => a + b, 0); // 10
  

🔧 Live Example: Filter Even Numbers

🧠 Utility Methods

• join() – Converts array to string
• reverse() – Reverses array
• sort() – Sorts alphabetically by default

let names = ["John", "Alice", "Bob"];
names.sort();   // ["Alice", "Bob", "John"]
names.reverse(); // ["John", "Bob", "Alice"]