The DayPilot.Row.events.forRange method returns an array of events that overlap the specified time range.
DayPilot.Row.events.forRange(start, end)
An array of DayPilot.Event objects.
var dp = new DayPilot.Scheduler("dp");
// ...
var events = dp.rows.find("R1").events.forRange("2019-01-10T00:00:00", "2019-01-15T00:00:00");