Add jest-light-runner

[GeoffreyBooth]

No description provided.

[nicolo-ribaudo]

Uh note that it's not a loader, it just can be used with loaders to do some of the things that jest does by using the VM module.

[GeoffreyBooth]

Uh note that it’s not a loader, it just can be used with loaders to do some of the things that jest does by using the VM module.

That’s fine, this is a list of “related projects,” not a list of loaders.

Is there a high-level explanation for how it does what it does? It’s not using the loader API, I assume, so how does it add the Jest globals and do functional mocking and the other Jest features that it supports?

[nicolo-ribaudo]

Ok, to be more specific... It does nothing (that's why I initially replied to this issue, I don't know if it "fits" in this list). It just uses import() to load the test files, after attaching the Jest globals to globalThis.

Its relationship with loaders is just that its (short) documentation shows that you can replace some of the Jest features, that Jest implements with vm.Module, with some loaders (that already exists, they were created by other people and not specifically for jest-light-runner).

It might add more value to add the loaders its README mentions to this list (ts-node and esmock).

However, it might be helpful to mention this package next to the Jest tracking issue link near the end of this file, for people who want to quickly now how to have a fully-compatible ESM environment when using Jest.

[GeoffreyBooth]

Thanks. I think it’s good to document how people are already solving some of the problems on our list, like mocking, because those existing solutions are things we very much want to be aware of as we continue to develop the loaders API.