Support indices.groups when compiling named groups in regexps

[ptomato]

Q	A
Fixed Issues?	None opened
Patch: Bug Fix?	No
Major: Breaking Change?	No
Minor: New Feature?	Yes (?)
Tests Added + Pass?	Yes
Documentation PR Link	No
Any Dependency Changes?	No
License	MIT

If a RegExp has the /d flag (hasIndices), match objects should have an extra property .indices with an array of the character indices that each subgroup matched. The indices array itself has a property .groups giving the matched character indices (or undefined) for each named capturing group.

This doesn't do anything to enable support for the /d flag, the .hasIndices property, or the returned indices object, if the environment does not support it, but it will populate .indices.groups in _wrapRegExp if .indices is present, so that the transform-named-capturing-groups-regex and proposal-duplicate-named-capturing-groups-regex plugins can take advantage of that support if it exists.

[babel-bot]

Build successful! You can test your changes in the REPL here: https://babeljs.io/repl/build/53301/

[nicolo-ribaudo]

I'm marking this as a bugfix because it just adds a missing piece of a proposal we already implemented (duplicate named groups), and it only works in browsers that already support /d. It would be a new feature if it implemented full support for /d, which we don't have yet.

[nicolo-ribaudo]

For the failing tests: Node.js 14 and older don't support /d, so they throw. You can fix it by:

• Moving the test from has-indices.js to has-indices/exec.js
• Adding an has-indices/options.json file that specifies the minimum Node.js version, like https://github.com/babel/babel/blob/672a58660f0b15691c44582f1f3fdcdac0fa0d2f/packages/babel-plugin-transform-named-capturing-groups-regex/test/fixtures/runtime/match-all/options.json