'SyntaxError: invalid identity escape in regular expression' in Firefox after upgrading to v6.0.0

[apasov]

I get this error in Firefox only:
SyntaxError: invalid identity escape in regular expression
though in Chrome it works okay.

Steps to reproduce:

git clone https://github.com/apasov/animatable-properties.git
cd animatable-properties
git reset --hard 3728a084984482ddcfc6a096a38c9b4c10a8c270

then open index.html in Firefox and you'll see blank page and the error in console.

After this commit fix: downgrade to camelcase v5.3.1 to fix syntax error in Firefox which fixes the error

git reset --hard cd3bda8f6a5972e7af4a71c5b65a3616c2852b01

reload index.html and it works as intended without errors

[sindresorhus]

@EthanSbbn Your issue is just that you didn't read the release notes which clearly state that Node.js 10 is required now.

[sindresorhus]

No, it’s expected that you read release notes. Especially for major versions.

[phun-ky]

@sindresorhus I have nodejs 12.16.3, and I get:

SyntaxError: invalid identity escape in regular expression

In firefox, with v6, but will downgrade. So it's not just a "You need a newer node version" issue. Perhaps specify that this is a ES2018 issue?

[sindresorhus]

@phun-ky Tests are passing on 12.16.3: https://travis-ci.com/github/sindresorhus/camelcase/jobs/321547607 You probably have multiple Node.js versions installed.

[phun-ky]

Hm, I use nvm, but the package is built / installed with the current node version active, as per spec right? For example, node sass (deps? ) needs to be recompiled/installed if you change versions.

Is not an issue for me, but dont be hasty saying that everything works just because the test passes.

[ThiefMaster]

SyntaxError: Invalid regular expression: /[_.\- ]+([\p{Alpha}\p{N}_]|$)/: Invalid property name in character class
    at camelCase (/home/adrian/dev/indico/src/node_modules/jest-validate/node_modules/camelcase/index.js:69:3)

With nodejs 12.16.1 on Gentoo. I'm not using nvm so it is not a case of using an older/different node version.

Also reproducible standalone:

[adrian@blackhole:/tmp]> node
Welcome to Node.js v12.16.1.
Type ".help" for more information.
> x = /[_.\- ]+([\p{Alpha}\p{N}_]|$)/gu;
Uncaught:
SyntaxError: Invalid regular expression: /[_.\- ]+([\p{Alpha}\p{N}_]|$)/: Invalid property name in character class

Oddly enough, in a node:12.6 docker container it works:

Welcome to Node.js v12.6.0.
Type ".help" for more information.
> x = /[_.\- ]+([\p{Alpha}\p{N}_]|$)/gu;
/[_.\- ]+([\p{Alpha}\p{N}_]|$)/gu

Update: I found out why it's failing: Node on Gentoo does not enable the icu USE flag by default, so when it compiles nodejs without libicu, the error above happens.