• Component: vis-timeline
• Version: 7.7.2
• Browser: Chrome and Firefox
• Example: https://stackblitz.com/edit/stackblitz-starters-dke6ux?file=package.json

Description

Long range items disappear from the timeline after data update if zoomed in so that the item start before visible range and ends after visible range.

Replication

For replication use the attached StackBlitz example.

1. click the Show All, it zooms to range where all items are visible
2. click the Set Data, items and groups are set and displayed properly
3. click the Zoom to Failure, it zooms to range where the issue happens
4. click the Set Data, items disappear but they should be displayed as they overlap the current range
5. click the Show All, items are displayed again as the range has changed

If you replace step 4 by subsequent clicks on Set Groups and Set Items then the items disappear at first but then they are displayed again. This is a possible workaround for us. We could execute setItems() in timer to make the items re-appear. However it introduces unpleasant flickering :(

Root Cause Analysis

The error happens in method _updateItemsInRange. There is a Binary Search algorithm implementation that under some combination of items simply skips the visible item. Most likely due to optimization reasons the items are at first sorted by start date and then also by end date. Then the binary search is applied that looks for first visible item by start and then by both start and end dates. If no first visible item is found then others are skipped. The proper approach would be to evaluate each item and check if it overlaps with visible range.