test: add a test for useSWRInfinite with initialData

[koba04]

This PR adds a test for useSWRInfinite with initialData.

I've added the test, but I'm still not sure of the expected behavior in the case.

How should useSWRInfinite behave combined with initialData?

• Does useSWRInfinite support initialData?
  • The initialData option is not mentioned in the document, but a related issue is being tagged as bug.
• If useSWRInfinite supports initialData, how should the initialData be handled?
  • Is the initialData stored in the cache store? Currently, it seems not to be stored in the cache. If so, I'll fix the issue.
    • https://github.com/vercel/swr/compare/master...koba04:add-test-for-swrInfinite-with-initial-data?expand=1#diff-e7360ba75395f51ce8b969b7e11a5c6e78d58ce8f45a86976eafe53f747d7487R508
• If useSWRInfinite doesn't support initialData, I think swr should warn the usage of initialData. Does it make sense?

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit aec19dd:

Sandbox	Source
SWR-Basic	Configuration
SWR-States	Configuration
SWR-Infinite	Configuration

[shuding]

Thanks, this is the expected behavior. useSWRInfinite should reuse initialData just like useSWR does because it's technically a wrapper of useSWR.

[shuding]

And for the question:

Is the initialData stored in the cache store?

Nope, initialData is considered as a fallback value of data, it won't be pre-filled into the cache.

[koba04]

Thank you!

[shunkakinoki]

hi guys! if I want to pull initialData into from thefallback key of SwrConfig in the page root what is the correct key to put in it? useSWRInfinite seems to have a special $inf$, attached to it.

https://swr.vercel.app/docs/with-nextjs