function collide(event1, event2) {
  const startInside = event1.start >= event2.start && event1.start <= event2.end
  const endInside = event1.end <= event2.end && event1.end > event2.start
  return startInside || endInside
}
Check if 2 events collide in time.

@param {Event} event1
@param {Event} event2
@return {Boolean}