react-native chrono - Invalid RegExp: Quantifier has nothing to repeat, js engine: hermes

[sajjad-karimi]

I've used chrono-node in react-native app and when I import chrono-node in app with hermes engine . I get the following error:

SyntaxError: Invalid RegExp: Quantifier has nothing to repeat, js engine: hermes

[wanasit]

Hello @sajjad-karimi sorry for my slow reply. I'm not aware of the Hermes engine.

Will try to see if we can support that engine.

[sanjeev-karat-zs0194]

We have a similar issue too. Do we have any workaround/suggestions?

[Nantris]

@wanasit the issue is related to this one: facebook/hermes#696

I tried using the core-js polyfill: core-js/proposals/regexp-named-groups - but then it just throws with Invalid RegExp: Invalid escape (Possibly related to this though I've never heard of unnecessary escapes breaking code execution) - (in this file: https://github.com/wanasit/chrono/blob/master/src/locales/ru/parsers/RUTimeUnitWithinFormatParser.ts)

The issue specifically is due to the use of named capture groups in the ZH and RU locale files, but I've not found any way to remedy the issue so far.

My only remaining idea is to use patch-package, which I guess I'll probably need to try.

[Nantris]

Confirmed that commenting out the RU and ZH parsers from the dist/index.js resolves my issue.

[Nantris]

Should be fixed in future versions of Hermes if the "completed" status of this issue is anything to go by: facebook/hermes#696

[wanasit]

Yes. I have checked out the latest build for the Hermes engine and it compiles the RegExp correctly now. This should make its way to react native app soon.

[mfbx9da4]

I tried commenting out ZH and RU and adding the core-js polyfill and my error turned into:

Maximum call stack size exceeded
    at module.exports (/.../node_modules/core-js/internals/is-regexp.js:12:9)

[wanasit]

As replied in #527. Please try update to Chrono v2.7.3
https://github.com/wanasit/chrono/releases/tag/v2.7.3

I have fixed the issue by switching to lazy-loading/creating RegEx patterns. In the longer term, we can only wait for Hermes Engine to support those patterns.

I'm closing this issue. Please comment on #527 or create a new issue for Hermes engine.