Reference FQL API reference Date difference() date.difference() Get the difference between two Dates. Signature difference(start: Date) => Number Description Subtract a date from the instance date to get the difference in number of days. Parameters Parameter Type Required Description start Date true Date to subtract from the instance date. Return value Type Description Number Difference between instance date and the provided start date, in days. Examples Date('2099-02-10').difference(Date('2099-01-01')) 40 add() subtract()