Function

hasFinishedWatching

hasFinishedWatching(
positionSeconds: number | null,
durationSeconds: number,
): positionSeconds is number
Whether the learner has watched a lesson to its end.
Parameters
- positionSeconds: number | null
  The stored position, or null when nothing is saved
- durationSeconds: number
  The lesson's length; <= 0 is treated as unknown and never finished
Returns positionSeconds is number
Whether the position has reached finishThresholdSeconds
Remarks
This is the rule that turns playback into completion: crossing it during playback marks the lesson complete through ProgressTracker, and it also lets a position saved before that rule existed read as complete with no migration.
Example
```
hasFinishedWatching(570, 600); // true
hasFinishedWatching(569, 600); // false
hasFinishedWatching(240, 0);   // false — a reading lesson
```
- Defined in lib/watch-progress/watch-progress.ts:111