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

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

/*---
description: Test the groups object of indices with matched and unmatched named captures.
includes: [compareArray.js]
esid: sec-makeindicesarray
features: [regexp-named-groups, regexp-match-indices]
info: |
  MakeIndicesArray ( S, indices, groupNames, hasGroups )
    11. For each integer _i_ such that _i_ >= 0 and _i_ < _n_, do
      e. If _i_ > 0 and _groupNames_[_i_ - 1] is not *undefined*, then
        i. Perform ! CreateDataProperty(_groups_, _groupNames_[_i_ - 1], _matchIndicesArray_).
---*/


const re = /(?<a>a).|(?<x>x)/d;
const result = re.exec("ab").indices;
assert.compareArray([0, 1], result.groups.a);
assert.sameValue(undefined, result.groups.x);