Calculate difference between 2 dates in ISO format in JavaScript/TS

Question

I have 2 dates in ISO format like so:

startDate: "2018-09-14T00:20:12.200Z"
endDate: "2018-09-16T00:18:00.000Z"

What I'm trying to do is calculate the difference between those 2 days. So with the given dates it would be 1 Day, 21 Hours, 47 Minutes and 40 Seconds (pardon me if the subtraction is not correct).

Tried to do using the following:

const start = new Date(startDate).getTime();
const end = new Date(endDate).getTime();
return Math.abs(end - start).toString();

However this doesn't seem to work.

Any clues?

Answer 1

The following works. Things to note:

1. getTime() is not needed as the new Date() constructor returns the time in milliseconds.
2. The date should always be in RFC2822 or ISO formats, else it becomes useless across various browsers, even while using moment.js.

If you can use moment.js, Get time difference using moment.

Refer this to know why only the standardized formats need to be used.

var unitmapping = {"days":24*60*60*1000,
                   "hours":60*60*1000,
                   "minutes":60*1000,
                   "seconds":1000};

function floor(value)
{
    return Math.floor(value)
}

function getHumanizedDiff(diff)
{
    return floor(diff/unitmapping.days)+" days "+
           floor((diff%unitmapping.days)/unitmapping.hours)+" hours "+
           floor((diff%unitmapping.hours)/unitmapping.minutes)+" minutes "+
           floor((diff%unitmapping.minutes)/unitmapping.seconds)+" seconds "+
           floor((diff%unitmapping.seconds))+" milliseconds";
}

console.log(getHumanizedDiff(new Date("2018-09-16T00:18:00.000Z") - new Date("2018-09-14T00:20:12.200Z")));
console.log(getHumanizedDiff(new Date("2018-09-16T00:18:00.000Z") - new Date("2018-09-04T00:20:02.630Z")));
console.log(getHumanizedDiff(new Date("2018-09-17T00:16:04.000Z") - new Date("2018-09-14T00:20:12.240Z")));

Answer 2

var startDate =  "2018-09-14T00:20:12.200Z"
var endDate = "2018-09-16T00:18:00.000Z"

const start = new Date(startDate).getTime();
const end = new Date(endDate).getTime();
const milliseconds = Math.abs(end - start).toString()
const seconds = parseInt(milliseconds / 1000);
const minutes = parseInt(seconds / 60);
const hours = parseInt(minutes / 60);
const days = parseInt(hours / 24);
const time = days + ":" + hours % 24 + ":" + minutes % 60 + ":" + seconds % 60;
console.log(time)