Typescript cannot parse named groups in regex

Question

I have a code line

regex = /^(?<aa>[0-9]{2})-(?<bb>[0-9]{6})-(?<cc>[0-9]{6})-(?<d>[0-9])$/;

And typescript (or is it webpack?) complains:

Module parse failed: Error parsing regular expression: Invalid regular expression: /^(?<aa>[0-9]{2})-(?<bb>[0-9]{6})-(?<cc>[0-9]{6})-(?<d>[0-9])$/: Invalid group (18:23)
    You may need an appropriate loader to handle this file type.

It seems to be a problem with the named groups. This is a valid regex in javascript.

I'm using typescript 2.9.2

I strongly prefer using named groups. What can I do to make them compile?

This seems to work on the typescript of jsfiddle, we need more information ... — Alexandre Elshobokshy
– Alexandre Elshobokshy, Commented Jan 29, 2019 at 10:40
So it's probably the version of typescript that is wrong. Can I change typescript version in jsfiddle? @IslamElshobokshy — Archeg
– Archeg, Commented Jan 29, 2019 at 10:47
@IslamElshobokshy BTW, wrapping expression in a string (new RegExp("..")) somewhat helps as it seems to switches off compile time validation. Still testing.. — Archeg
– Archeg, Commented Jan 29, 2019 at 10:49
I don't think you can change typescript version in jsfiddle, I'm looking into it too. Using RegExp() is a good idea, do keep us updated :-) I can't seem to be able to reproduce, I'm sorry... — Alexandre Elshobokshy
– Alexandre Elshobokshy, Commented Jan 29, 2019 at 10:50

bug-a-lot · Accepted Answer · 2019-01-29 15:19:53Z

5

That is actually not a valid regular expression in javascript according to https://regexr.com/. And Firefox and Edge.

Or rather, it depends on the browser. Support for named groups has been added to ES2018. So your mileage might vary.

See http://kangax.github.io/compat-table/es2016plus/ for compatibility.

Typescript compiler is not the one throwing the error it's your webpack module loader. I would try setting the target to ES2018 and see if that works.

Alternatively see the answer about array destructuring on Named capturing groups in JavaScript regex? .

answered Jan 29, 2019 at 15:19

bug-a-lot

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ncaq · Accepted Answer · 2019-07-24 08:43:07Z

1

Unfortunately transpiling the regex itself is not supported by Typescript itself. See issue #24531.

If you're using Babel aswell in your build chain, consider plugin-transform-named-capturing-groups-regex

edited Jul 24, 2019 at 8:43

ncaq

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answered Mar 11, 2019 at 7:04

Jay Wick

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