Jest: Use `react-is` in `pretty-format`

[SimenB]

Right now we have manual $$typeof checks: https://github.com/facebook/jest/blob/af1ab24649798bcf0f7ce6ec5b3cf4ba2a53b5eb/packages/pretty-format/src/plugins/ReactElement.ts#L37-L72

It would be cool to instead use react-is

[Prabhakar-17]

I would like to work on this.

[SimenB]

That's awesome @Prabhakar-17! Go for it 🙂

[Prabhakar-17]

Running yarn install is giving me this error: weak compilation error. Any idea how to resolve this?

[SimenB]

I'd just remove the dependency in jest-leak-detector and ignore the test warnings surrounding it. I've tried to get it to work on a windows image without luck 🙂

[Prabhakar-17]

@SimenB How can I test my changes to make sure something else is not broken because of the change. yarn test result looks good, anything specific that needs to be done in this case?

[SimenB]

If our tests pass, then you're good - we have quite good test coverage on pretty-format. Looking forward to the PR!

[Prabhakar-17]

There's problem with the @types/react-is package. I have raised an issue here

[SimenB]

@types/react is at 16.8.6 in this repo (latest) (updated a few days ago)

https://github.com/facebook/jest/blob/5ba35be3ef64090bae5e04f51fd170529fba3d1a/yarn.lock#L1772-L1778

So that should be fixed?

[mackness]

Hi @SimenB, I took a crack at this. Let me know if you think my changes make sense. https://github.com/facebook/jest/pull/8058

Thanks!

[Prabhakar-17]

@SimenB Yes, it worked. Will submit the PR