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.
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 |
isRegExp
checkThe 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
Desktop | ||||||
---|---|---|---|---|---|---|
match |
50 | 79 | 40 | No | 37 | 10 |
Mobile | ||||||
---|---|---|---|---|---|---|
match |
50 | 50 | 40 | 37 | 10 | 5.0 |
Server | |
---|---|
match |
6.0.0 |
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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