// parse delivery date provided by the courier
const deliveryDate = moment('2017-10-20 09:30', 'YYYY-MM-DD HH:mm');
console.log(deliveryDate.toString()); // Fri Oct 20 2017 09:30:00 GMT+0100
// calculate relative time from now to delivery date
const timeToWait = moment().to(deliveryDate);
console.log(timeToWait); // in 4 days