RunKit + npm: moment

var moment = require("moment") var d = moment.duration("P64D") console.log(`input: 'P64D' expected: '2 Months 4 Days' actual: '${d.months()} Months ${d.days()} Days'`) d = moment.duration(`P1Y${30}D`) console.log(`input: 'P1Y${30}D' expected: 13 Months' actual: '${d.asMonths()} Months'`) d = moment.duration(`P1YT${30*24}H`) console.log(`input: 'P1YT${30*24}H' expected: 13 Month' actual: '${d.asMonths()} Months'`) d = moment.duration(`P1YT${31*24}H`) console.log(`input: 'P1YT${31*24}H' expected: 13 Months 1 Day' actual: '${d.asMonths()} Month ${d.days()} Day'`)