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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.

For more information, see RegExp.prototype[@@match]() and String.prototype.match().

Try it

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 except undefined), it indicates that the object is not intended to be used as a regular expression object.

Examples

Marking a RegExp as not a regex

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 object will be considered as not a regular expression object. The methods startsWith and endsWith won't throw a TypeError as a consequence.

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

Specifications

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet Deno Node.js
match
50
79
40
No
37
10
50
50
40
37
10
5.0
1.0
6.0.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Symbol/match