String Functions in JavaScript

JavaScript provides a variety of built-in methods to manipulate strings. Here are some commonly used string functions:

1. length property:

Returns the length of a string.

JavaScript
let text = "Hello, world!";
console.log(text.length); // Output: 13

2. toUpperCase() and toLowerCase():

Converts a string to uppercase or lowercase

JavaScript
let text = "Hello, World!";
console.log(text.toUpperCase()); // Output: "HELLO, WORLD!"
console.log(text.toLowerCase()); // Output: "hello, world!"

3. charAt():

Returns the character at a specified index.

JavaScript
let text = "JavaScript";
console.log(text.charAt(0)); // Output: "J"

4. indexOf() and lastIndexOf():

Finds the index of a substring within a string.

JavaScript
let text = "Hello, world!";
console.log(text.indexOf("world")); // Output: 7
console.log(text.lastIndexOf("o")); // Output: 8

5. slice():

Extracts a part of a string and returns it as a new string.

JavaScript
let text = "JavaScript is fun";
console.log(text.slice(0, 10)); // Output: "JavaScript"

6. substring():

Similar to slice(), but cannot accept negative indexes.

JavaScript
let text = "JavaScript is fun";
console.log(text.substring(0, 10)); // Output: "JavaScript"

7. replace():

Replaces a substring with a new substring.

JavaScript
let text = "Hello, world!";
console.log(text.replace("world", "JavaScript")); // Output: "Hello, JavaScript!"

8. split():

Splits a string into an array based on a delimiter.

JavaScript
let text = "apple,banana,orange";
console.log(text.split(",")); // Output: ["apple", "banana", "orange"]

9. trim():

Removes whitespace from both ends of a string.

JavaScript
let text = "   Hello, world!   ";
console.log(text.trim()); // Output: "Hello, world!"

10. includes():

Checks if a string contains a certain substring.

JavaScript
let text = "Hello, JavaScript!";
console.log(text.includes("JavaScript")); // Output: true

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