obal_Objects/Object/constructor)
    2. [ ` Object.prototype.__proto__ ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/proto) Deprecated 
  13. Methods 
    1. [ ` Object.prototype.__defineGetter__() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__defineGetter__) Deprecated 
    2. [ ` Object.prototype.__defineSetter__() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__defineSetter__) Deprecated 
    3. [ ` Object.prototype.__lookupGetter__() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__lookupGetter__) Deprecated 
    4. [ ` Object.prototype.__lookupSetter__() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__lookupSetter__) Deprecated 
    5. [ ` Object.prototype.hasOwnProperty() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/hasOwnProperty)
    6. [ ` Object.prototype.isPrototypeOf() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/isPrototypeOf)
    7. [ ` Object.prototype.propertyIsEnumerable() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/propertyIsEnumerable)
    8. [ ` Object.prototype.toLocaleString() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/toLocaleString)
    9. [ ` Object.prototype.toString() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/toString)
    10. [ ` Object.prototype.valueOf() ` ](/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/valueOf)

##  In this article

  * Description 
  * Examples 
  * Specifications 
  * Browser compatibility 
  * See also 

#  RegExp.prototype.unicodeSets

The **` unicodeSets ` ** accessor property of [ ` RegExp ` ](/en-
US/docs/Web/JavaScript/Reference/Global_Objects/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 `
](/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/unicode) 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 ` ](/en-
US/docs/Web/JavaScript/Reference/Global_Objects/SyntaxError) . With the ` v `
flag, you get all features mentioned in the ` u ` flag description, plus:

  * The [ ` \p ` ](/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Unicode_character_class_escape) escape sequence can be additionally used to match properties of strings, instead of just characters. 
  * The [ character class ](/en-US/docs/Web/JavaScript/Reference/Regular_expressions/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 ](/en-US/docs/Web/JavaScript/Reference/Regular_expressions/Character_class#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
](/en-
US/docs/Web/JavaScript/Reference/Regular_expressions/Character_class#v-mode_character_class)
.

**Note:** The ` v ` mode does not interpret grapheme clusters as single
characters; they are still multiple code points. For example, ` /[ðºð³]/v
` is still able to match ` "ðº" ` .

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{Lette