RegExp.prototype.unicodeSets
The unicodeSets
accessor property of RegExp
instances returns whether or not the v
flag is used with this regular expression.
Description
RegExp.prototype.unicodeSets
has the value true
if the v
flag was used; otherwise, false
. The v
flag is an "upgrade" to the u
flag that enables more Unicode-related features. ("v" is the next letter after "u" in the alphabet.) Because u
and v
interpret the same regex in incompatible ways, using both flags results in a SyntaxError
. With the v
flag, you get all features mentioned in the u
flag description, plus:
- The
\p
escape sequence can be additionally used to match properties of strings, instead of just characters. - The character class syntax is upgraded to allow intersection, union, and subtraction syntaxes, as well as matching multiple Unicode characters.
- The character class complement syntax
[^...]
constructs a complement class instead of negating the match result, avoiding some confusing behaviors with case-insensitive matching. For more information, see Complement classes and case-insensitive matching.
Some valid u
-mode regexes become invalid in v
-mode. Specifically, the character class syntax is different and some characters can no longer appear literally. For more information, see v
-mode character class.
Note: The v
mode does not interpret grapheme clusters as single characters; they are still multiple code points. For example, /[πΊπ³]/v
is still able to match "πΊ"
.
The set accessor of unicodeSets
is undefined
. You cannot change this property directly.
Examples
Using the unicodeSets property
js
const regex = /[\p{Script_Extensions=Greek}&&\p{Letter}]/v;
console.log(regex.unicodeSets); // true
Specifications
Specification |
---|
ECMAScript Language Specification # sec-get-regexp.prototype.unicodesets |
Browser compatibility
BCD tables only load in the browser
See also
RegExp.prototype.lastIndex
RegExp.prototype.dotAll
RegExp.prototype.global
RegExp.prototype.hasIndices
RegExp.prototype.ignoreCase
RegExp.prototype.multiline
RegExp.prototype.source
RegExp.prototype.sticky
RegExp.prototype.unicode
- RegExp v flag with set notation and properties of strings on v8.dev (2022)