RegExp Quantifiers
RegExp Quantifiers
Quantifiers define the numbers of characters or expressions to match.
const pattern = /0+/;
JavaScript RexExp Quantifiers
Revised July 2025
| Code | Description |
|---|---|
| x+ | Matches at least one x |
| x* | Matches zero or more occurrences of x |
| x? | Matches zero or one occurrences of x |
| x{n} | Matches n occurences of x |
| x{n,m} | Matches from n to m occurences of x |
| x{n,} | Matches n or more occurences of x |
RegExp + Quantifier
x+ matches matches at least onex.
Example
A global search for at least one "o":
const pattern = /lo+/g;
let result = text.match(pattern);
RegExp * Quantifier
x* matches zero or more occurrences ofx.
Example
A global search for an "l", followed by zero or more "o" characters:
const pattern = /lo*/g;
let result = text.match(pattern);
RegExp ? Quantifier
x? matches zero or one occurrences of x.
Example
A global search for "1", followed by zero or more "0" characters:
const pattern = /10?/g;
let result = text.match(pattern);
RegExp {n} Quantifier
x{n} matchesn occurences ofx.
A global search for a string that contains a sequence of four digits:
let pattern = /\d{4}/g;
let result = text.match(pattern);
RegExp {n,m} Quantifier
x{n,m} matches fromn tom occurences ofx.
A global search for a substring that contains a sequence of three to four digits:
let pattern = /\d{3,4}/g;
let result = text.match(pattern);
RegExp {n,} Quantifier
x{n,} matchesn or more occurences ofx.
A global search for a sequence of at least three digits:
let pattern = /\d{3,}/g;
let result = text.match(pattern);
Regular Expression Methods
Regular ExpressionSearch andReplace 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 |
