React-native 82

[hosseinmd]

Describe the bug

i am testing react-native 82 with rspack i got flow type error

System Info

react-naive 82
rspack

Re.Pack Version

5.2.1

Reproduction

react-native 82

Steps to reproduce

upgrade to 82

[hosseinmd]

i use "@callstack/repack/babel-swc-loader" and it is fixed
but compile time increase to 4x slower than Repack.getJsTransformRules
we moved to rspack swc because of compile time, now there is no gain.
what is the solution?

[jbroma]

i use "@callstack/repack/babel-swc-loader" and it is fixed but compile time increase to 4x slower than Repack.getJsTransformRules we moved to rspack swc because of compile time, now there is no gain. what is the solution?

Hey @hosseinmd,

as described in this blogpost newer RN versions introduced flow syntax which is impossible to strip with flow-remove-types - an utility that we used until this point to get rid of the flow-typing and compile them later with just SWC. Re.Pack 5.2 introduced babel-swc-loader to work around this issue by always including Babel in the pipeline.

This solution is a good default for most setups but it comes with a performance hit as you've noticed. You can always tweak the loader rules and use the old getJSTransformRules for non-flow modules/libraries and only keep the babel-swc-loader for necessary parts & it should work just fine.

[jbroma]

There is an ongoing RFC for shipping RN without flow types: react-native-community/discussions-and-proposals#810