RegExp Character Classes
Character Classes are characters enclosed in square brackets [].
A character class matches any character from a set within brackets:
// Match Digits
const pattern = /[0-9]/;
JavaScript Regex Character Classes
Revised July 2025
| Class | Description |
|---|---|
| [a] | Matches the character between the brackets |
| [^a] | Matches all characters NOT between the brackets |
| [abc] | Matches all characters between the brackets |
| [^abc] | Matches all characters NOT between the brackets |
| [a-z] | Matches all characters in the range from a to z |
| [^a-z] | Matches all characters NOT in the range from a to z |
| [0-9] | Matches all characters in the range from 0 to 9 |
| [^0-9] | Matches all characters NOT in the range from 0 to 9 |
Example [HW]
A global search for the characters "H" and "W" in a string:
let text = "Hello World!";
const pattern = /[HW]/g;
let result = text.match(pattern);
Example [A-Z]
A global search for the upper case characters "A" to "Z" in a string:
let text = "This is W3School";
const pattern = /[A-Z]/g;
let result = text.match(pattern);
Example [1234]
A global search for the characters "1", "2", "3" and "4" in a string:
let text = "123456789";
const pattern = /[1234]/g;
let result = text.match(pattern);
Example [1-4]
A global search for the characters "1" to "4" in a string:
let text = "123456789";
const pattern = /[1-4]/g;
let result = text.match(pattern);
Note
[01234] is the same as [0-4]
[abcde] is the same as [a-e]
Regular Expression Methods
Regular Expression Search and Replace can be done with different methods.
These are the most common:
String Methods
| Method | Description |
|---|---|
| match(regex) | Returns an Array of results |
| matchAll(regex) | Returns an Iterator of results |
| replace(regex) | Returns a new String |
| replaceAll(regex) | Returns a new String |
| search(regex) | Returns the index of the first match |
| split(regex) | Returns an Array of results |
RegExp Methods
| Method | Description |
|---|---|
| regex.exec() | Returns an Iterator of results |
| regex.test() | Returns true or false |
