Core-js: Named Capture groups in RegExp constructor

[kalvenschraut]

I am receiving an unexpected qualifier error in IE 11 using the following expression which is coming from the RegExp constructor polyfill.

const pathRegex = /^(?<schema>[-a-z]+)\.(?<table>[-a-z]+)\.(?<fieldPath>[a-zA-Z_[\].0-9]+)$/; 
const regex =  RegExp(`^${pathRegex.source.substring(1,pathRegex.source.length - 1)}#(?<bindingNumber>[0-9]+)$`);

I wanted to use pathRegex by itself but the normal regex variable is suppose to be made up of the pathRegex variable. Right now I can work around this by copying it over, but I would prefer to use the variable to construct the whole regex.

I am using core-js@3 and [email protected]
I must say the usage flag recently introduced is making my job of maintaining IE 11 compatibility a lot easier!

[AlokTakshak]

@zloirock I would like to contribute , can you tell me what needs to be done?

[zloirock]

@AlokTakshak you could find some basic info here. As an example, you could take a look at Number constructor wrapper for handling modern number literals.

[zloirock]

If you have any more detailed questions - just ask me.

[zloirock]

RegExp constructor should parse patterns with NCG syntax and return a regex created from pattern allowed in the old version of the language with internal metadata about NCG. RegExp.prototype.exec should be patched for creating groups property with the required result.

[zloirock]

Seems something like here https://github.com/commenthol/named-regexp-groups, but in the main class.

[zloirock]

1. Not exactly - as I wrote, it should return a real regex instance, not something regex-like. It's just an example. Also, you could take a look at related babel transform output and the helper
2. It theoretically could require changes not only on RegExp.prototype.exec, but also in some other methods, for example, on RegExp.prototype[@@replace], but I don't think that on match since String methods related RegExp should call related RegExp methods and they should call RegExp.prototype.exec under the hood. See the spec.