RegExp.prototype[@@match]() - JavaScript 编辑

The [@@match]() method retrieves the matches when matching a string against a regular expression.

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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

Browser compatibility

BCD tables only load in the browser

See also

• String.prototype.match()
• RegExp.prototype[@@replace]()
• RegExp.prototype[@@search]()
• RegExp.prototype[@@split]()
• RegExp.prototype.exec()
• RegExp.prototype.test()