🧩 String Methods

Last Updated: 3rd October 2025

Strings in JavaScript come with many built-in methods that help in text processing — like changing case, searching, replacing, splitting, trimming, etc.

Hinglish Tip 🗣: String methods wo tools hain jinke through hum text ke sath khel sakte hain — jaise uppercase/lowercase banana, words nikalna, replace karna, ya length check karna.

length method → Returns the total number of characters in the string.

let text = "JavaScript";
console.log(text.length); // 10

Change Case

let text = "JavaScript";
console.log(text.toUpperCase()); // JAVASCRIPT
console.log(text.toLowerCase()); // javascript

Extract Part

let text = "JavaScript";
console.log(text.slice(0, 3)); // Jav (0 to 2)
console.log(text.slice(4)); // Script (from index 4 to end)
console.log(text.slice(-6)); // Script (last 6 characters)
console.log(word.substring(3, 7));

Note : substring() method not work for negative index, but slice() method work for negative index.

Search

let msg = "Hello JavaScript World!";

console.log(msg.indexOf("JavaScript")); // 6
console.log(msg.lastIndexOf("l")); // 21
console.log(msg.includes("World")); // true
console.log(msg.startsWith("Hello")); // true
console.log(msg.endsWith("!")); // true

Replace & Repeat

let txt = "I love JS. JS is awesome!";

console.log(txt.replace("JS", "JavaScript"));
// I love JavaScript. JS is awesome!

console.log(txt.replaceAll("JS", "JavaScript"));
// I love JavaScript. JavaScript is awesome!

console.log("Hi! ".repeat(3)); // Hi! Hi! Hi!

Trim Extra Space

let text = "     JavaScript     ";
console.log(spaceText.trim()); // "JavaScript"
console.log(spaceText.trimStart()); // "JavaScript   "
console.log(spaceText.trimEnd());

Split & Join

let data = "Apple,Banana,Mango";
let fruits = data.split(",");
console.log(fruits); // ["Apple", "Banana", "Mango"]

let fruitsStr = fruits.join(",");
console.log(fruitsStr); // "Apple,Banana,Mango"

Character Access

let text = "JavaScript";
console.log(text.charAt(0)); // J
console.log(text[text.length - 1]); // t
console.log(text.charCodeAt(0)); // 74
console.log(String.fromCharCode(74)); // J

Concatenation

let first = "Hello";
let second = "World";

console.log(first.concat(" ", second)); // Hello World
console.log(first + " " + second); // Hello World

🎯 Exercises

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