JavaScript Strings

A JavaScript String is a sequence of characters, typically used to represent text.

In JavaScript, there is no character type (similar to Python and different from C, C++, and Java), so a single character string is used when we need a character. Like Java and Python, strings in JavaScript are immutable.

Create using Literals – Recommended

We can either use a single quote or a double quote to create a string. It is recommended to be consistent with your choice throughout your code.

// Using Single Quote
let s1 = 'abcd';
console.log(s1);
 
// Using Double Quote
let s2 = "abcd";
console.log(s2);

Output:

abcd
abcd

Create using Constructor

The String Constructor is less common for direct string creation.

let s = new String('abcd');
console.log(s);

Output:

[String: 'abcd']

Template Literals (String Interpolation)

You can create strings using Template Literals. Template literals allow you to embed expressions within backticks (``) for dynamic string creation, making it more readable and versatile.

let s1 = 'Coders';
let s2 = `You are learning from ${s1}`;
console.log(s2);

Output:

You are learning from Coders

Empty String

You can create an empty string by assigning either single or double quotes with no characters in between.

let s1 = '';
let s2 = "";
console.log(s1);
console.log(s2);

Multiline Strings (ES6 and later)

You can create a multiline string using backticks (`) with template literals.

let s = `
    This is a
    multiline
    string`;
console.log(s);

Output:

    This is a
    multiline
    string

Basic Operations on JavaScript Strings

1. Finding the length of a String

let s = 'JavaScript';
let len = s.length;
console.log("String Length: " + len);

Output:

String Length: 10

2. String Concatenation

let s1 = 'Java';
let s2 = 'Script';
let res = s1 + s2;
console.log("Concatenated String: " + res);

Output:

Concatenated String: JavaScript

3. Escape Characters

const s1 = "'C75' is a learning portal";
const s2 = '"C75" is a learning portal';
const s3 = "\\C75\\ is a learning portal";
console.log(s1);
console.log(s2);
console.log(s3);

Output:

'C75' is a learning portal
"C75" is a learning portal
\C75\ is a learning portal

4. Breaking Long Strings

const s = "'Coding75' is " + "a learning portal";
console.log(s);

Output:

'Coding75' is a learning portal

5. Find Substring of a String

let s1 = 'JavaScript Tutorial';
let s2 = s1.substring(0, 10);
console.log(s2);

Output:

JavaScript

6. Convert String to Uppercase and Lowercase

let s = 'JavaScript';
let uCase = s.toUpperCase();
let lCase = s.toLowerCase();
console.log(uCase);
console.log(lCase);

Output:

JAVASCRIPT
javascript

7. String Search in JavaScript

let s1 = 'def abc abc';
let i = s1.indexOf('abc');
console.log(i);

Output:

8. String Replace in JavaScript

let s1 = 'Learn HTML at GfG';
let s2 = s1.replace('HTML', 'JavaScript');
console.log(s2);

Output:

Learn JavaScript at GfG

9. Trimming Whitespace from String

let s1 = '    Learn JavaScript       ';
let s2 = s1.trim();
console.log(s2);

Output:

Learn JavaScript

10. Access Characters from String

let s1 = 'Learn JavaScript';
let s2 = s1[6];
console.log(s2);
s2 = s1.charAt(6);
console.log(s2);

Output:

J
J

11. String Comparison in JavaScript

let str1 = "John";
let str2 = new String("John");
console.log(str1 == str2);
console.log(str1.localeCompare(str2));

Output:

true
0

12. Passing JavaScript String as Objects

const str = new String("Coding75");
console.log(str);

Output:

[String: 'Coding75']

Are Strings Created by the `new` Keyword the Same as Normal Strings?

const str1 = new String("Coding75");
const str2 = "Coding75";
console.log(str1 == str2);
console.log(str1 === str2);

Output:

true
false

Javascript Array Reference Javscript Strings Methods