RegExp.leftContext unsupported

[ammarahm-ed]

Migrating a NativeScript project from v8 to use quickjs that uses [email protected] and I see this error.

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/leftContext

The API seems to be deprecated but it still works in the v8 engine. Is it possible to support this 🤔

[bnoordhuis]

I looked into that a while ago but test262 has practically no coverage left (besides "does the property exist?") so it's hard to ensure it and other legacy properties function correctly.

I'm also not 100% positive they can be implemented without regressing performance of the common case. They're getters, not plain properties, so that helps, but you still need to store the state somewhere.

If you want to look into it, it's the legacy-regexp option in test262.conf, currently marked 'skip'.

[ammarahm-ed]

@bnoordhuis thanks, I will see if I can add support for this.