RegExp.prototype[@@match]()
The [@@match]()
method retrieves the matches when
matching a string against a regular expression.
Syntax
regexp[Symbol.match](str)
Parameters
str
-
A
String
that is a target of the match.
Return value
An Array
containing the entire match result and any parentheses-captured
matched results, or null
if there were no matches.
Description
This method is called internally in String.prototype.match()
.
For example, the following two examples return same result.
'abc'.match(/a/);
/a/[Symbol.match]('abc');
This method exists for customizing match behavior within RegExp
subclasses.
Examples
Direct call
This method can be used in almost the same way as
String.prototype.match()
, except the different this
and the
different arguments order.
let re = /[0-9]+/g;
let str = '2016-01-02';
let result = re[Symbol.match](str);
console.log(result); // ["2016", "01", "02"]
Using @@match
in subclasses
Subclasses of RegExp
can override the [@@match]()
method to
modify the default behavior.
class MyRegExp extends RegExp {
[Symbol.match](str) {
let result = RegExp.prototype[Symbol.match].call(this, str);
if (!result) return null;
return {
group(n) {
return result[n];
}
};
}
}
let re = new MyRegExp('([0-9]+)-([0-9]+)-([0-9]+)');
let str = '2016-01-02';
let result = str.match(re); // String.prototype.match calls re[@@match].
console.log(result.group(1)); // 2016
console.log(result.group(2)); // 01
console.log(result.group(3)); // 02
Specifications
Specification |
---|
ECMAScript Language Specification # sec-regexp.prototype-@@match |
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