indexOf

split(separator, limit)

• Splits a string into an array based on a separator.

let str = "apple,banana,grape";
console.log(str.split(",")); // ["apple", "banana", "grape"]

trim()

• Removes whitespace from both ends of a string.

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

toLowerCase() / toUpperCase()

• Converts the string to lowercase or uppercase.

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

replace(search, replacement)

• Replaces part of a string with another value.

let str = "I love JavaScript";
console.log(str.replace("JavaScript", "Python")); // "I love Python"

includes(substring)

• Checks if a string contains a specific substring.

console.log(str.includes("ll")); // true

charAt(index)

• Returns the character at a specified position.

let str = "Hello";
console.log(str.charAt(1)); // "e"

substring(start, end)