RegExp Quantifiers
Regular Expression (Regex) quantifiers define how many times the preceding character, group, or character class must occur in a string. They control the boundaries of your matches, allowing patterns to be flexible.
// Match at least one zero
const pattern = /0+/;
JavaScript RexExp Quantifiers
Revised July 2025
| Col 1 | Col 2 |
|---|---|
| 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 one x.
Example
let text = "Hellooo World! Hello W3Schools!";
const pattern = /o+/g;
let result = text.match(pattern);
RegExp * Quantifier
x* matches zero or more occurrences of x.
Example
let text = "Hellooo World! Hello W3Schools!";
const pattern = /lo*/g;
let result = text.match(pattern);
RegExp ? Quantifier
x? matches zero or one occurrences of x.
Example
let text = "1, 100 or 1000?";
const pattern = /10?/g;
let result = text.match(pattern);
RegExp {n} Quantifier
x{n} matches n occurences of x.
let text = "100, 1000 or 10000?";
let pattern = /\d{4}/g;
let result = text.match(pattern);
RegExp {n,m} Quantifier
x{n,m} matches from n to m occurences of x.
let text = "100, 1000 or 10000?";
let pattern = /\d{3,4}/g;
let result = text.match(pattern);
RegExp {n,} Quantifier
x{n,} matches n or more occurences of x.
let text = "100, 1000 or 10000?";
let pattern = /\d{3,}/g;
let result = text.match(pattern);
Regular Expression Methods
Regular Expression Search and Replace can be done with different methods.
These are the most common:
String Methods
| Col 1 | Col 2 |
|---|---|
| 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
| Col 1 | Col 2 |
|---|---|
| Method | Description |
| regex.exec() | Returns an Iterator of results |
| regex.test() | Returns true or false |
Note: See Also: JavaScript RegExp Tutorial JavaScript RegExp Flags JavaScript RegExp Character Classes JavaScript RegExp Meta Characters JavaScript RegExp Assertions JavaScript RegExp Groups JavaScript RegExp Patterns JavaScript RegExp Objects JavaScript RegExp Methods
