Stale while invalidate

[theKashey]

Inside RRR there are two logics that are fighting with each other a little bit:

• one is stale while invalidate
  • will use existing resource if it’s available and not expired

    react-resource-router/src/resources/controllers/resource-store/index.tsx

    Line 161 in b0e55fa

    if (cached && shouldUseCache(cached)) {

  • or will “fallback” to the exiting while loading the new one

    react-resource-router/src/resources/controllers/resource-store/index.tsx

    Line 227 in b0e55fa

    data: maxAge === 0 ? null : prevSlice.data,

• another one proactively removes all already expired pieces
  

  react-resource-router/src/resources/controllers/resource-store/index.tsx

  Line 444 in b0e55fa

  if (slice && (!slice.expiresAt || slice.expiresAt < Date.now())) {

  • so the logic mentioned above will have “nothing”

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Questions

• there is a comment that we "need" to clean resourced during transition
  https://github.com/atlassian-labs/react-resource-router/blob/b0e55faeafdc6f193e5fda338e5533e6f88725cf/src/resources/controllers/resource-store/index.tsx#L427C1-L431C25

  • "why?"

• there is a logic that can reuse previous response while the new one is loading

  • probably this is how refresh works. More likely intentional.
  • this logic is never used during transition. Is it intentional?

• if one removes cleanExpiredResources

  • would it lead to any memory leaks?
  • would it lead to any behavior change?
    • and if yes (and it will), how end user can detect such change

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Proposal - add explicit stateWhileInvalidate flag for resource and exempt them from cleanExpiredResources giving control to the end user.