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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

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
match 50 79 40 No 37 10
Mobile
Android webview Chrome for Android Firefox for Android Opera for Android Safari on iOS Samsung Internet
match 50 50 40 37 10 5.0
Server
Node.js
match 6.0.0

See also

© 2005–2018 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://wiki.developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/match