Loading from storage VS loading from Dropbox. If credentials are present, wait before showing site to avoid sudden updates?
Invalidating credentials when requests fail > Require reauthentication.
Handling conflicts when the Dropbox file is newer than the last known file saved by the browser.
Polling changes to the file to detect conflicts / figure out how to use Dropbox revisions to avoid conflicts. What do to if two devices update the file around the same time?
Saving and loading tracked data using the Dropbox API.
This follows the earlier export/import feature in https://github.com/Silverfeelin/SkyGame-Planner/issues/1 which would enable syncing across devices.
Some things to take into consideration:
For now I got some experimental code in this branch which supports authenticating through Dropbox and saving/reading a simple JSON file: https://github.com/Silverfeelin/SkyGame-Planner/tree/dropbox