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

The [@@matchAll] method returns all matches of the regular expression against a string.

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The source for this interactive example is stored in a GitHub repository. If you'd like to contribute to the interactive examples project, please clone https://github.com/mdn/interactive-examples and send us a pull request.

Syntax

regexp[Symbol.matchAll](str)

Parameters

str

A String that is a target of the match.

Return value

An iterator.

Description

This method is called internally in String.prototype.matchAll(). For example, the following two examples return same result.

'abc'.matchAll(/a/);

/a/[Symbol.matchAll]('abc');

This method exists for customizing the behavior of matchAll() in RegExp subclasses.

Examples

Direct call

This method can be used in almost the same way as String.prototype.matchAll(), except for the different value of this and the different order of arguments.

let re = /[0-9]+/g;
let str = '2016-01-02';
let result = re[Symbol.matchAll](str);

console.log(Array.from(result, x => x[0]));
// ["2016", "01", "02"]

Using @@matchAll in subclasses

Subclasses of RegExp can override the [@@matchAll]() method to modify the default behavior.

For example, to return an Array instead of an iterator:

class MyRegExp extends RegExp {
  [Symbol.matchAll](str) {
    const result = RegExp.prototype[Symbol.matchAll].call(this, str);
    if (!result) {
      return null;
    } else {
      return Array.from(result);
    }
  }
}

const re = new MyRegExp('([0-9]+)-([0-9]+)-([0-9]+)', 'g');
const str = '2016-01-02|2019-03-07';
const result = str.matchAll(re);
console.log(result[0]); // [ "2016-01-02", "2016", "01", "02" ]
console.log(result[1]); // [ "2019-03-07", "2019", "03", "07" ]

Specifications

Specification
ECMAScript (ECMA-262) The definition of 'RegExp.prototype[@@matchAll]' in that specification.

Browser compatibility

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See also

• String.prototype.matchAll()
• Symbol.matchAll