JSTests/test262/test/built-ins/RegExp/match-indices/indices-groups-object.js

// Copyright 2019 Ron Buckton. All rights reserved.
// This code is governed by the BSD license found in the LICENSE file.

/*---
description: The groups object of indices is created with CreateDataProperty
includes: [propertyHelper.js]
esid: sec-makeindicesarray
features: [regexp-named-groups, regexp-match-indices]
info: |
  MakeIndicesArray ( S, indices, groupNames )
    8. If _groupNames_ is not *undefined*, then
      a. Let _groups_ be ! ObjectCreate(*null*).
    9. Else,
      a. Let _groups_ be *undefined*.
    10. Perform ! CreateDataProperty(_A_, `"groups"`, _groups_).
---*/


// `groups` is created with Define, not Set.
let counter = 0;
Object.defineProperty(Array.prototype, "groups", {
  set() { counter++; }
});

let indices = /(?<x>.)/.exec("a").indices;
assert.sameValue(counter, 0);

// `groups` is writable, enumerable and configurable
// (from CreateDataProperty).
verifyProperty(indices, 'groups', {
    writable: true,
    enumerable: true,
    configurable: true
});