Symbol.match static data property represents the well-known symbol
String.prototype.match() method looks up this symbol on its first argument for the method used to match an input string against the current object. This symbol is also used to determine if an object should be treated as a regex.
The well-known symbol
|Property attributes of
This function is also used to identify if objects have the behavior of regular expressions. For example, the methods
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.
The following code will throw a
"/bar/".startsWith(/bar/); // Throws TypeError, as /bar/ is a regular expression // and Symbol.match is not modified.
However, if you set
false, the object will be considered as not a regular expression object. The methods
endsWith won't throw a
TypeError as a consequence.
const re = /foo/; re[Symbol.match] = false; "/foo/".startsWith(re); // true "/baz/".endsWith(re); // false
|ECMAScript Language Specification |
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