itch-tab-fetching.md

itch app tab fetching strategy:

• grab what we can from local db (fast, doesn't usually fail)
  • emit that so it can be rendered already
• fire API requests
  • there may be several (multiple pages of games, for example)
    • emit at each step so they can be rendered as soon as we got it
  • any API request might fail
    • because we're offline
    • because of server/proxy issues
    • because credentials are invalid (expired, revoked)
• any time we get new data, we should emit it
  • if it's the same data, it shouldn't trigger a re-render
    • pretty much no choice but to do a deep comparison here :/
    • p.s timestamps are for humans, not skipping deep comparisons
  • remote data & local data should be reconciled
    • example: if local has all 4 pages of a collection but remote only has 1 so far, games shouldn't temporarily disappear from view. we can only be sure a game disappeared after remote is done fetching all its pages.
• fetching shouldn't hang forever
  • if we should retry network requests, do we just cancel the fetch and schedule it again later, or do we handle retry inside the fetch?
• we should be able to cancel fetching
  • don't do unnecessary API requests
• "when to fetch" is an open question
  • when opening a new tab
  • when switching to a tab
  • on app focus
  • when we come back online
  • when tab is manually refreshed
  • every once in a while (30 minutes right now)
  • other corner cases: game tab after a game is purchased, for example
• fetching should be debounced/deduplicated
  • several refresh conditions may happen at once, but we don't want 3x or 4x the API requests going out