date-fns: 1

const intervalToDuration = require("date-fns/intervalToDuration"); const parseISO = require("date-fns/parseISO"); // ok const int1 = { start: parseISO('2020-05-01T00:00:00'), // Date end: parseISO('2020-07-01T00:00:00'), // Date }; const dur1 = intervalToDuration(int1); console.log(dur1); // Object {days: 0, hours: 0, minutes: 0, months: 2, seconds: 0, years: 0}