🔠 Day 8 — Strings & String Methods in JavaScript

Welcome to Day 8 🌟 — Today’s session is all about **Strings**, one of the most common data types in JavaScript. Strings represent text and allow you to store names, messages, or any sequence of characters.

💬 1️⃣ What is a String?

A string is a sequence of characters written inside quotes.

let name = "Rahul";
let greeting = 'Hello World';
let message = `Welcome ${name}!`; // Template literal

🧩 2️⃣ String Properties

Strings behave like arrays — they have a .length property and can be accessed using index numbers.

let text = "JavaScript";
console.log(text.length); // 10
console.log(text[0]); // J
console.log(text[text.length - 1]); // t

🎨 3️⃣ Common String Methods

toUpperCase() & toLowerCase()

let city = "Hyderabad";
console.log(city.toUpperCase());
console.log(city.toLowerCase());

slice(start, end)

let word = "JavaScript";
console.log(word.slice(0, 4)); // Java

substring() vs substr()

let str = "Learning JavaScript";
console.log(str.substring(9, 19)); // JavaScript

replace() and replaceAll()

let text2 = "I love JavaScript";
console.log(text2.replace("JavaScript", "React"));

trim()

Removes extra spaces from start and end.

let messy = "   Hello World   ";
console.log(messy.trim());

🧮 4️⃣ Searching Strings

• indexOf() — position of first occurrence
• includes() — checks if substring exists
• startsWith() / endsWith()

let msg = "Frontend development is fun!";
console.log(msg.includes("Frontend")); // true
console.log(msg.startsWith("Front")); // true
console.log(msg.endsWith("fun!")); // true

💡 5️⃣ Template Literals

Backticks (`) make it easy to include variables inside strings.

let user = "Rahul";
let lang = "JavaScript";
console.log(`Hey ${user}, welcome to ${lang} learning!`);

🧠 6️⃣ Practice Task

1. Store your full name and extract first and last name using slice().
2. Convert a sentence to uppercase and lowercase.
3. Check if your name starts with a vowel using startsWith().
4. Use template literals to create a greeting sentence.

🎯 Summary

Today, you learned how to manipulate strings using various built-in methods. Next, we’ll explore **Objects and JSON**, which are essential for structured data and real-world applications.

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