The getTime() method returns the number of milliseconds since January 1, 1970 for the specified date.
DayPilot.Date.getTime();
Returns a number of milliseconds since 1970-01-01.
const milliseconds = new DayPilot.Date("1970-01-01").getTime(); // 0
DayPilot.Date Class
Availability of this API item in DayPilot editions: