JavaScript Strings

A string in JavaScript is a sequence of characters, enclosed within single quotes ('') or double quotes ("").

Creating Strings

You can create strings using either single or double quotes.

const singleQuotedString = 'Hello, world!';
const doubleQuotedString = "Hello, world!";

String Methods

JavaScript provides various methods for working with strings, such as:

• length: Returns the length of the string.
• toUpperCase(): Converts the string to uppercase.
• toLowerCase(): Converts the string to lowercase.
• charAt(index): Returns the character at the specified index.
• indexOf(substring): Returns the index of the first occurrence of the specified substring.
• substring(startIndex, endIndex): Returns the substring between the specified indices.
• split(separator): Splits the string into an array of substrings based on the specified separator.
• replace(searchValue, replaceValue): Replaces occurrences of a specified value with another value.

const str = "Hello, world!";
console.log(str.length); // Output: 13
console.log(str.toUpperCase()); // Output: HELLO, WORLD!
console.log(str.indexOf("world")); // Output: 7
console.log(str.substring(7)); // Output: world!
console.log(str.split(", ")); // Output: ["Hello", "world!"]
console.log(str.replace("world", "John")); // Output: Hello, John!

String Concatenation

You can concatenate strings using the + operator or the concat() method.

const firstName = "John";
const lastName = "Doe";
const fullName = firstName + " " + lastName;
console.log(fullName); // Output: John Doe

Strings are fundamental data types in JavaScript and are used extensively for storing and manipulating text-based data. Understanding string methods and operations is crucial for effective string manipulation in JavaScript.