JavaScript String

In this tutorial, you will learn about JavaScript string with the help of examples.

JavaScript string is a primitive data type that is used to work with texts. For example,

const name = 'John';

Create JavaScript Strings

In JavaScript, strings are created by surrounding them with quotes. There are three ways you can use quotes.

  • Single quotes: 'Hello'
  • Double quotes: "Hello"
  • Backticks: `Hello`

For example,

//strings example
const name = 'Peter';
const name1 = "Jack";
const result = `The names are ${name} and ${name1}`;

Single quotes and double quotes are practically the same and you can use either of them.

Backticks are generally used when you need to include variables or expressions into a string. This is done by wrapping variables or expressions with ${variable or expression} as shown above.

You can also write a quote inside another quote. For example,

const name = 'My name is "Peter".';

However, the quote should not match the surrounding quotes. For example,

const name = 'My name is 'Peter'.'; // error

Access String Characters

You can access the characters in a string in two ways.

  • One way is to treat strings as an array. For example,
const a = 'hello';
console.log(a[1]); // "e"
  • Another way is to use the method charAt(). For example,
const a = 'hello';
console.log(a.charAt(1)); // "e"

JavaScript Strings are immutable

In JavaScript, strings are immutable. That means the characters of a string cannot be changed. For example,

let a = 'hello';
a[0] = 'H';
console.log(a); // "hello"

However, you can assign the variable name to a new string. For example,

let a = 'hello';
a = 'Hello';
console.log(a); // "Hello"

JavaScript is Case-Sensitive

JavaScript is case-sensitive. That means in JavaScript, the lowercase and uppercase letters are treated as different values. For example,

const a = 'a';
const b = 'A'
console.log(a === b); // false

In JavaScript, a and A are treated as different values.


JavaScript Multiline Strings

To use a multiline string, you can either use the + operator or the \ operator. For example,

// using the + operator
const message1 = 'This is a long message ' +
    'that spans across multiple lines' + 
    'in the code.'

// using the \ operator
const message2 = 'This is a long message \
that spans across multiple lines \
in the code.'

JavaScript String Length

To find the length of a string, you can use built-in length property. For example,

const a = 'hello';
console.log(a.length); // 5

JavaScript String Objects

You can also create strings using the new keyword. For example,

const a = 'hello';
const b = new String('hello');

console.log(a); // "hello"
console.log(b); // "hello"

console.log(typeof a); // "string"
console.log(typeof b); // "object"

Note: It is recommended to avoid using string objects. Using string objects slows down the program.


JavaScript String Methods

Here are the commonly used JavaScript String methods:

Method Description
charAt(index) returns the character at specified index
concat() joins two or more strings
replace() replaces a string with another string
split() converts the string to an array of strings
substr(start, length) returns a part of a string
substring(start,end) returns a part of a string
slice(start, end) returns a part of a string
toLowerCase() returns the passed string in lower case
toUpperCase() returns the passed string in upper case
trim() removes whitespace from the strings
includes() searches for a string and returns a boolean value
search() searches for a string and returns a position of a match

Example: JavaScript String Methods

const text1 = 'hello';
const text2 = 'world';
const text3 = '     JavaScript    ';

// concatenating two strings
const result1 = text1.concat(' ', text2);
console.log(result1); // "hello world"

// converting the text to uppercase
const result2 = text1.toUpperCase();
console.log(result2); // HELLO

// removing whitespace from the string
const result3 = text3.trim();
console.log(result3); // JavaScript

// converting the string to an array
const result4 = text1.split();
console.log(result4); // ["hello"]

// slicing the string
const result5= text1.slice(1, 3);
console.log(result5); // "el"

JavaScript String() Function


The String() function is used to convert various data types to strings. For example,

const a = 225; // string
const b = true; // boolean

//converting to number
const result1 = String(a);
const result2 = String(b);

console.log(result1); // "225"
console.log(result2); // "true"

If you want to learn more about the string conversion, visit JavaScript Type Conversion.


Escape Character

You can use the backslash escape character \ to include special characters in a string. For example,

const name = 'My name is \'Peter\'.';
console.log(name);

Output

My name is 'Peter'.

In the above program, the same quote is included using \.

Here are the other ways that you can use \:

Code Output
\" include double quote
\\ include backslash
\n new line
\r carriage return
\v vertical tab
\t horizontal tab
\b backspace
\f form feed