Webpack erroring on ?? and ?. when doing snowpack build

[Retsam]

We've got a snowpack + TS project that was working correctly, but after some npm dependencies were updated, we're now seeing our snowpack builds fail, due to webpack erroring on ?? and ?. syntax.

Module parse failed: Unexpected token (1:4889)
File was processed with these loaders:

• ../node_modules/babel-loader/lib/index.js
• ../node_modules/@snowpack/plugin-webpack/plugins/import-meta-fix.js
• ../node_modules/@snowpack/plugin-webpack/plugins/proxy-import-resolve.js
  You may need an additional loader to handle the result of these loaders.

I've confirmed the issue isn't snowpack's version itself, I reinstalled the original version of snowpack and I'm seeing the same issue. However I'm not sure which dependency specifically would be responsible for transforming that syntax. I'd assume something inside babel-loader, but that also has not changed version, either, so some specific babel plugin perhaps?

But I'm not sure how to debug any farther because I'm not sure precisely what babel config snowpack uses and how to trace down what part is misbehaving.