Feature request: support the plugin option for swc compiler

[mattcasey]

I'm a bit out of my depth here. I am trying to integrate swc-plugin-transform-import into my Next.js build so that our imports of @mui are converted into default exports. The only solution that works is to fall back to the Babel compiler and use babel-plugin-transform-imports.

I couldn't find definitive documentation about the API from swc, but it seems like they support a 'plugin' option which allows transformations in Javascript. This is also based on what I've seen in the links i shared below. With the changes I've included, I can see that my plugin is getting passed to the 'transform' method of the SWC binary on my machine: swc-darwin-x64 but my investigation ends there. I can tell that my plugin function is still not being called, but I'm hoping it's a simple fix maybe to continue passing the plugin function down into swc.

The code I've added to next.config.js can be found here: #30862 (comment). I am trying to apply the plugin to the next-swc-loader. I tried adding a new rule, tried using swc-loader, etc. but ran into other issues, so I'm just asking for next-swc-loader to support this additional field instead.

Two related issues posted against next.js related to people wanting to transform their imports:

• NextJs compiling extremely slow #29559
• SWC equivalent for `babel-transform-imports`? #30862

Other links:

• The plugin in question: https://www.npmjs.com/package/swc-plugin-transform-import which uses the plugin option for swc-loader.
• Someone saying that "plugin" is a supported option on swc-loader: Plugin support swc-project/swc-loader#29
• SWC plugin docs: https://swc.rs/docs/usage/plugins (although they don't mention how to include a plugin with webpack)

[timneutkens]

There's a PR open to add support for mapping urls with SWC: #34969

The plugins key that you're referring to is a swc-loader feature that is intentionally not supported in Next.js as it requires passing from Rust -> JS -> Rust -> JS which has a massive performance overhead. We're also working on Rust-based plugins for SWC which would solve other cases but for your case you'll probably want what we're adding in #34969.

[timneutkens]

Left a comment.

[mattcasey]

OK, thanks! Will close my PR, looking forward to the update