The minutes() method returns the minute component of the duration as an integer number of full minutes.
DayPilot.Duration.minutes()Returns the minute part of the duration. The value contains full minutes only, so it is always an integer.
Use DayPilot.Duration.totalMinutes() when you need the entire duration converted to minutes instead of just the minute component.
const minutes = new DayPilot.Duration("2020-01-01T00:00:00", "2020-01-05T12:30:15").minutes(); // 30DayPilot.Duration.totalMinutes()
External Drag and Drop [doc.daypilot.org]