JavaScript RegExp Patterns
RexExp Flags Reference
Revised July 2025
| Flag | Description |
|---|---|
| /d | Performs substring matches (new 2022) |
| /g | Performs a global match (find all) |
| /i | Performs case-insensitive matching |
| /m | Performs multiline matching |
| /s | Allows . (dot) to match line terminator characters (new 2018) |
| /u | Enables Unicode support (new 2015) |
| /v | An upgrade to the /u flag for better Unicode support (new 2025) |
| /y | Performs a "sticky" search (new 2015) |
RexExp Brackets
| [] | Description |
|---|---|
| [a] | Find the character between the brackets |
| [^a] | Find any character different from the one between the brackets |
| [abc] | Find any of the characters between the brackets |
| [^abc] | Find any character NOT between the brackets |
| [A-Z] | Find any character in the range from A to Z (any letter) |
| [^A-Z] | Find any character NOT in the range from A to Z |
| [0-9] | Find any character in the range from 0 to 9 (any digit) |
| [^0-9] | Find any character NOT in the range from 0 to 9 |
| (x|y) | Find any of the alternatives specified |
RexExp Metacharacters
| Char | Description |
|---|---|
| ^ | Matches from beginning of a string, or the beginning of a line if the m (multiline) flag is set |
| $ | Matches from the end of a string, or the end of a line if the m (multiline) flag is set |
| . | Matches any single (wildcard) character, except line terminators like \n and \r |
| \w | Matches any word character (alphanumeric and underscore _) |
| \W | Matches any non-word character |
| \d | Matches any digit (0-9) |
| \D | Matches any non-digit character |
| \s | Matches any whitespace character like space, tab \t, and newline \n |
| \S | Matches any non-whitespace character |
| \b | Matches any match at the beginning or end of a word |
| \B | Matches any match, but not at the beginning or end of a word |
| [\b] | Matches any backspace character |
| \0 | Matches any NULL character |
| \n | Matches any new line character |
| \f | Matches any form feed character |
| \r | Matches any carriage return character |
| \t | Matches any tab character |
| \v | Matches any vertical tab character |
| \p{} | Matches any character based on its Unicode character property (new 2018) |
| \P{} | Matches any character NOT based on its Unicode character property (new 2018) |
| \ddd | Matches the character specified by an octal number xxx |
| \xhh | Matches the character specified by a hexadecimal number hh |
| \uhhhh | Matches the Unicode character specified by a hexadecimal number hhhh |
RexExp Quantifiers
| Quant | Description |
|---|---|
| n+ | Matches any string that contains at least one n |
| n* | Matches any string that contains zero or more occurrences of n |
| n? | Matches any string that contains zero or one occurrences of n |
| n{X} | Matches any string that contains a sequence of X n's |
| n{X,Y} | Matches any string that contains a sequence of X to Y n's |
| n{X,} | Matches any string that contains a sequence of at least X n's |
| n$ | Matches any string with n at the end of it |
| ^n | Matches any string with n at the beginning of it |
| ?=n | Matches any string that is followed by a specific string n |
| ?!n | Matches any string that is not followed by a specific string n |
