What is the best practice for adding polyfills to support older browsers?

[gregmartyn]

The answer for this earlier GitHub discussion is apparently in Discord, but the Discord page isn't loading for me. What was the answer? Thanks.

#10635

https://discord.com/channels/770287896669978684/1376408046854733885

[sergiodxa]

RR apps uses import in the browser, which means browsers that doesn’t support that will never load the JS at all, so you at least need ES2015 and actually more as ESM was not added to browsers in 2015 but later

This is not configurable
The recommendation is to use progressive enhancement so older browsers can use plain html behavior like an actual form submission

This was the answer on Discord, aka even if you added a polyfill you won't be able to support browsers without ESM support, for anything else you can just import it in entry.client like the original discussion mentioned.