Dragging single-day task in year view shows NaN and breaks date calculation #4766
Description
Description
In the Gantt chart year view, a task that starts and ends on the same calendar day but spans the full day (for example, start: Mon Jul 21 2025 00:00:00 GMT+0200, end: Mon Jul 21 2025 23:59:59 GMT+0200) is not treated as a milestone, which is intended.
When dragging the start or end of this task, the drag interaction appears normal, but the date calculation fails. The tooltip shows NaN for the start or end date. Also throws the following error "Error: Maximum call stack size exceeded".
The issue occurs in the get taskWidth() function, where the calculation:
(taskEnd.getDate() - taskStart.getDate()) / totalDaysInStartMonth
Steps To Reproduce
https://stackblitz.com/edit/angular-fjr9prry-3bxhfvg1
or
https://stackblitz.com/edit/angular-fjr9prry-ykfgqtng