JavaScript Strings

A string is used to store text in JavaScript. For example, a person’s name, a message, or a city name can be stored as a string.

let name = "Aman";
let city = "Delhi";

console.log(name);
console.log(city);

Output:

Aman
Delhi

Creating Javascript Strings

We can create a string using single quotes, double quotes, or backticks.

let firstName = "Aman";
let lastName = 'Kumar';
let message = `Hello!`;

All three store text as strings.

String Length

The length property tells us how many characters are in a string.

let text = "JavaScript";

console.log(text.length);

Output:

10

Spaces are also counted as characters.

Accessing String Characters

Each character in a string has an index number. The first character starts at index 0.

let name = "Aman";

console.log(name[0]);
console.log(name[2]);

Output:

A
a

We can use the index to get a particular character from a string.

JavaScript String Methods

String methods are ready-made functions that help us work with strings.

toUpperCase()

It changes all letters to uppercase.

let text = "hello";

console.log(text.toUpperCase());

Output:

HELLO

toLowerCase()

It changes all letters to lowercase.

let text = "JAVASCRIPT";

console.log(text.toLowerCase());

Output:

javascript

trim()

The trim() method removes extra spaces from the beginning and end of a string.

let text = "   Hello   ";

console.log(text.trim());

Output:

Hello

includes()

The includes() method checks whether a string contains some text.

It returns true or false.

let text = "I love JavaScript";

console.log(text.includes("JavaScript"));

Output:

true

slice()

The slice() method takes a part of a string.

let text = "JavaScript";

console.log(text.slice(0, 4));

Output:

Java

The first number is the starting index, and the second number is where the extraction stops.

replace()

The replace() method replaces some text with other text.

let text = "I like Java";

console.log(text.replace("Java", "JavaScript"));

Output:

I like JavaScript

JavaScript String Search

indexOf()

The indexOf() method returns the position of the first occurrence of some text.

let text = "Hello JavaScript";

console.log(text.indexOf("JavaScript"));

Output:

6

If the text is not found, indexOf() returns -1.

lastIndexOf()

The lastIndexOf() method finds the position of the last occurrence of some text.

let text = "JavaScript is fun. JavaScript is useful.";

console.log(text.lastIndexOf("JavaScript"));

Output:

20

JavaScript Template Strings

Template strings use backticks instead of quotes. They make it easy to put variables inside a string using ${}.

let name = "Aman";
let age = 14;

let message = `My name is ${name} and I am ${age} years old.`;

console.log(message);

Output:

My name is Aman and I am 14 years old.

This is called string interpolation.

JavaScript Escape Characters

Escape characters allow us to use special characters inside strings. For example, \" allows us to use double quotes inside a string.

let message = "He said, \"Hello!\"";

console.log(message);

Output:

He said, "Hello!"

Another useful escape character is \n, which creates a new line.

let text = "Hello\nJavaScript";

console.log(text);

Output:

Hello
JavaScript

Quick Recap

• Strings are used to store text.
• Strings can use single quotes, double quotes, or backticks.
• length counts the characters in a string.
• String characters use index numbers starting from 0.
• Methods like toUpperCase(), trim(), includes(), slice(), and replace() help us work with strings.
• indexOf() and lastIndexOf() help find text inside a string.
• Template strings make it easy to add variables inside text.
• Escape characters help us write special characters in strings.

Frequently Asked Questions (FAQs)

Written by Shubhranshu Shekhar, who has trained 20000+ students in coding.

Nidhi Srivastav