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.

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.

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

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
ECMAScript (ECMA-262)
The definition of 'Symbol.match' in that specification.

Browser compatibility

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DesktopMobileServer
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung InternetNode.js
matchChrome Full support 50Edge Full support 79Firefox Full support 40IE No support NoOpera Full support 37Safari Full support 10WebView Android Full support 50Chrome Android Full support 50Firefox Android Full support 40Opera Android Full support 37Safari iOS Full support 10Samsung Internet Android Full support 5.0nodejs Full support 6.0.0

Legend

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See also