Better jest support

[IronLu233]

I try to use swc in my company project's unit test.

But I found there are some extra work for jest.

In general, we have to implement a swc-jest like babel-jest

And I think the code for jest transform should not in @swc/core package.

How can I use a jest plugin, witch is build from Rust code?

[kdy1]

Currently, code for jest lives in @swc/core, because I'm still working on the rust plugin system.

For now, you can use @swc/jest, which depends on @swc/core.
https://www.npmjs.com/package/@swc/jest

[kdy1]

I'm working on rust-based plugin system, but it requires some decisions about APIs and it's delaying a lot.
I expect the plugin system itself not to be hard to implement, but determining API is very hard.

[IronLu233]

you can use @swc/jest

I means, now @swc/jest is not work for some jest features.
For example, jest.mock('module-path')should hoist before module import.
and in jest test code can override modules named import see #2049
Seems Rust plugin system is still in progress,
Is it means I have to implement "jest transform" using the Visitor API in https://swc.rs/docs/usage-plugin now?

[kdy1]

For jest, you can use https://github.com/swc-project/swc/tree/71080dbd26fdb09bc6b6e69b3e088e3994b704ce/ecmascript/ext-transforms

[IronLu233]

Yes, this is what I need. I will try to use it and make it better with some PRs.