upgrade @firebase/polyfill core-js

[mhDuke]

npm WARN deprecated core-js@3.6.5:
core-js@<3.23.3 is no longer maintained and not recommended for usage due to the number of issues. Because of the V8 engine whims, feature detection in old core-js versions could cause a slowdown up to 100x even if nothing is polyfilled. Some versions have web compatibility issues.

Please, upgrade your dependencies to >=3.23.3 of core-js.

[google-oss-bot]

I couldn't figure out how to label this issue, so I've labeled it for a human to triage. Hang tight.

[g-30]

second this

[dorji-tshering]

Same issue here. Just installed firebase right now. I hope it will be resolved soon!

[MarwanSdeek]

same issue while installing the latest firebase@9.9.2.

[playtinum]

Bump

[hsubox76]

So the good news is that core-js code isn't used in the code for any Firebase SDK products installed through NPM. It was included in @firebase/polyfill package which is currently only bundled into the compat CDN builds (where Firebase is included using script tags, and applying only to urls that end with -compat.js). We forgot to remove it from the dependencies in package.json (which is why it's installing during yarn/npm install) but the code isn't imported into any Firebase code.

NPM users and users of the v9 CDN scripts shouldn't need to worry. I'll remove @firebase/polyfill from the dependencies and you should stop getting that warning after the next release.

As of v9 we've stopped updating @firebase/polyfill and expect users to provide their own so I'll also remove the polyfill import from the compat CDNs.