Offline Support

[CarsonF]

• Service worker:
  • Load static files
  • Handle page loads. Maybe respond with single entrypoint / which has our env config and let app do a render instead of a hydrate
  • API files/images maybe?
• Queries:
  • apollo-cache-persist restore cached query data on load.
    • Cache policy needs to be changed in order to prevent stale cache
      • Maybe cache-and-network
      • We don't want that to keep hitting network though. Maybe cache-first for nextFetchPolicy. I'm not sure that works across component (un)mounts...
      • These can be applied in defaultOptions instead of every query.
• Mutations:
  • apollo-link-queue to store pending mutations when offline
  • apollo-link-serialize execute mutations in serial instead of all in parallel
    • This example uses the same serialization key for all mutations.
  • All operations will need optimisticResponses, so that the UI can show the pending value before it sent to server.
  • The queued list still needs to be persisted.
    • Most of the data (name, query, variables, other context) is JSON-able so that part is relatively straight forward.
    • The update function is not. Maybe we can extract all update functions and store them in a central place via Babel. Then JSON persist the function name & args.
• Show UI for syncing to server when coming back online. "Sending 4/5 changes"
• How to handle errors from API?
• How to de-dupe pending operations for same thing? (like auto-save for the same field)
• How to handle different IDs from dependent operations? i.e. Create Project -> Create Engagement. If create engagement references a temporary project ID then how does that get switched over to the real ID from server?

┆Issue is synchronized with this Monday item by Unito