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. We can use either of the two, but 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
Recommended Links
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 = 'gfg';
let s2 = `You are learning from ${s1}`;
console.log(s2);
Output
You are learning from gfg
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);
Output
Multiline Strings (ES6 and later)
You can create a multiline string using backticks (“) with template literals. The backticks allows you to span the string across multiple lines, preserving the line breaks within the string.
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
You can find the length of a string using the length property.
let s = 'JavaScript';
let len = s.length;
console.log("String Length: " + len);
Output
String Length: 10
2. String Concatenation
You can combine two or more strings using + Operator.
let s1 = 'Java';
let s2 = 'Script';
let res = s1 + s2;
console.log("Concatenated String: " + res);
Output
Concatenated String: JavaScript
3. Escape Characters
We can use escape characters in string to add single quotes, dual quotes, and backslash.
\' - Inserts a single quote
\" - Inserts a double quote
\\ - Inserts a backslash
const s1 = "\'GfG\' is a learning portal";
const s2 = "\"GfG\" is a learning portal";
const s3 = "\\GfG\\ is a learning portal";
console.log(s1);
console.log(s2);
console.log(s3);
Output
'GfG' is a learning portal "GfG" is a learning portal \GfG\ is a learning portal
4. Breaking Long Strings
We will use a backslash to break a long string in multiple lines of code.
const s = "'GeeksforGeeks' is \
a learning portal";
console.log(s);
Output
'GeeksforGeeks' is a learning portal
Note: This method might not be supported on all browsers. A better way to break a string is by using the string addition.
const s = "'GeeksforGeeks' is a"
+ " learning portal";
console.log(s);
Output
'GeeksforGeeks' is a learning portal
5. Find Substring of a String
We can extract a portion of a string using the substring() method.
let s1 = 'JavaScript Tutorial';
let s2 = s1.substring(0, 10);
console.log(s2);
Output
JavaScript
6. Convert String to Uppercase and Lowercase
Convert a string to uppercase and lowercase using toUpperCase() and toLowerCase() methods.
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
Find the first index of a substring within a string using indexOf() method.
let s1 = 'def abc abc';
let i = s1.indexOf('abc');
console.log(i);
Output
4
8. String Replace in JavaScript
Replace occurrences of a substring with another using replace() method.
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
Remove leading and trailing whitespaces using trim() method.
let s1 = ' Learn JavaScript ';
let s2 = s1.trim();
console.log(s2);
Output
Learn JavaScript
10. Access Characters from String
Access individual characters in a string using bracket notation and charAt() method.
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
There are some inbuilt methods that can be used to compare strings such as the equality operator and another like localeCompare() method.
let str1 = "John";
let str2 = new String("John");
console.log(str1 == str2);
console.log(str1.localeCompare(str2));
Output
true 0
Note: The Equality operator returns true, whereas the localeCompare method returns the difference of ASCII values.
12. Passing JavaScript String as Objects
We can create a JavaScript string using the new keyword.
const str = new String("GeeksforGeeks");
console.log(str);
Output
[String: 'GeeksforGeeks']
Are the strings created by the new keyword is same as normal strings?
No, the string created by the new keyword is an object and is not the same as normal strings.
const str1 = new String("GeeksforGeeks");
const str2 = "GeeksforGeeks";
console.log(str1 == str2);
console.log(str1 === str2);
Output
true false
JavaScript Strings – FAQs
What is a string in JavaScript?
A string is a sequence of characters used to represent text. Strings are one of the fundamental data types in JavaScript and are enclosed in single quotes (‘), double quotes (“), or backticks (`).
How do you create a string?
You can create a string by enclosing characters in single quotes, double quotes, or backticks.
Examples:
- ‘Hello’
- “World”
- `Hello World`
What are template literals?
Template literals are strings enclosed in backticks (`) and allow for embedded expressions using ${expression}. They can span multiple lines and include interpolated variables and expressions.
Example: `Hello, ${name}!`
How do you access characters in a string?
You can access characters in a string using bracket notation and the index of the character. The index starts at 0 for the first character.
Example: str[0]
How do you find the length of a string?
You can find the length of a string using the length property.
Example: str.length
How do you concatenate strings?
You can concatenate strings using the + operator or the concat() method.
Example: str1 + str2 or str1.concat(str2)
