Symbol.match

The Symbol.match well-known symbol specifies the matching of a regular expression against a string. This function is called by the String.prototype.match() method.

Property attributes of Symbol.match
Writable no
Enumerable no
Configurable no

Description

This function is also used to identify if objects have the behavior of regular expressions. For example, the methods String.prototype.startsWith(), String.prototype.endsWith() and String.prototype.includes(), check if their first argument is a regular expression and will throw a TypeError if they are. Now, if the match symbol is set to false (or a Falsy value), it indicates that the object is not intended to be used as a regular expression object.

Examples

Disabling the isRegExp check

The following code will throw a TypeError:

"/bar/".startsWith(/bar/); 

// Throws TypeError, as /bar/ is a regular expression
// and Symbol.match is not modified.

However, if you set Symbol.match to false, the isRegExp check (that uses the match property) will indicate that the object is not a regular expression object. The methods startsWith and endsWith won't throw a TypeError as a consequence.

var re = /foo/;
re[Symbol.match] = false;
"/foo/".startsWith(re); // true
"/baz/".endsWith(re);   // false

Specifications

Specification Status Comment
ECMAScript 2015 (6th Edition, ECMA-262)
The definition of 'Symbol.match' in that specification.
Standard Initial definition.
ECMAScript 2017 Draft (ECMA-262)
The definition of 'Symbol.match' in that specification.
Draft  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari
Basic support 50 40 (40) No support No support No support
Feature Android Chrome for Android Firefox Mobile (Gecko) IE Mobile Opera Mobile Safari Mobile
Basic support No support No support 40.0 (40) No support No support No support

See also

Document Tags and Contributors

 Contributors to this page: ZeikJT, fscholz, mattmazzola, Brettz9
 Last updated by: ZeikJT,