Class
Returns the saved position in seconds, or null when none is persisted.
Persists the position in seconds; idempotent.
Writes every pending position now, through the Server Action.
Hands every pending position to navigator.sendBeacon, for a page being hidden.
The browser's
PlaybackPositionRepository: every position reaches the learner store at once, and the server at most once every SERVER_WRITE_INTERVAL_MS per lesson.Remarks
The player hands over a position every second or two. Showing it on every progress bar is free; writing each one to a hosted database is not. So the first position of a window is written at once, later ones only replace the pending value, and the window's close writes the latest. flush writes a pending position now — for a pause, a seek, the end of the video, leaving the page within the app — and flushWithBeacon hands it to
navigator.sendBeacon, the one request a closing page is allowed to finish.A refused write is not rolled back: the next write carries a newer position anyway (capability
learner-state).