swc-loader much slower if react refresh plugin is enabled

[piotrpalek]

Hey, I've tried integrating react fast refresh with swc-loader, and the result is that if I add new ReactRefreshPlugin() to the plugins: [] list in webpack, swc-loader is dog slow (well, as slow as if I was using babel). If I remove this plugin it's way faster, any ideas what could be wrong? Is this expected?

[pmmmwh]

Hey, I've tried integrating react fast refresh with swc-loader, and the result is that if I add new ReactRefreshPlugin() to the plugins: [] list in webpack, swc-loader is dog slow (well, as slow as if I was using babel). If I remove this plugin it's way faster, any ideas what could be wrong? Is this expected?

Can you share a bit more about your setup, or create a reproducible example? There have been performance fixes in the 0.5.x releases, but we do inject another loader into the bundling chain so maybe that would slow things down.

[piotrpalek]

Thanks for the info :)

Sorry if I'm light on details, but I'm still trying to come up with a reproducible example, and I can't share the whole repo since it's work related. I was asking to see if maybe this was known, could help me in research knowing where to look :)

I'll be hacking around and let you know if/when I manage to reproduce it or solve the issue

[pmmmwh]

Thanks for the info :)

Sorry if I'm light on details, but I'm still trying to come up with a reproducible example, and I can't share the whole repo since it's work related. I was asking to see if maybe this was known, could help me in research knowing where to look :)

I'll be hacking around and let you know if/when I manage to reproduce it or solve the issue

It could very much be due to source map generation, or if you have a lot of files that needs to be processed. Those are the two most likely points of clogging.

[marco2216]

Hi @piotrpalek did you find any solution? We are experiencing the same issue on a large project

[piotrpalek]

@marco2216 no sorry :( for now we just didn't move to swc-loader

[marco2216]

@piotrpalek Feel free to try out if this change helps, I'm not actually sure if it has anything to do with swc-loader, but it significantly improved our transpile speed https://github.com/pmmmwh/react-refresh-webpack-plugin/pull/669