Javascript return number of days,hours,minutes,seconds between two dates

Does anyone can link me to some tutorial where I can find out how to return days , hours , minutes, seconds in javascript between 2 unix datetimes?

I have:

var date_now = unixtimestamp;
var date_future = unixtimestamp;

I would like to return (live) how many days,hours,minutes,seconds left from the date_now to the date_future.

Solution 1:

Just figure out the difference in seconds (don't forget JS timestamps are actually measured in milliseconds) and decompose that value:

// get total seconds between the times
var delta = Math.abs(date_future - date_now) / 1000;

// calculate (and subtract) whole days
var days = Math.floor(delta / 86400);
delta -= days * 86400;

// calculate (and subtract) whole hours
var hours = Math.floor(delta / 3600) % 24;
delta -= hours * 3600;

// calculate (and subtract) whole minutes
var minutes = Math.floor(delta / 60) % 60;
delta -= minutes * 60;

// what's left is seconds
var seconds = delta % 60;  // in theory the modulus is not required

EDIT code adjusted because I just realised that the original code returned the total number of hours, etc, not the number of hours left after counting whole days.

Solution 2:

Here's in javascript: (For example, the future date is New Year's Day)

DEMO (updates every second)

var dateFuture = new Date(new Date().getFullYear() +1, 0, 1);
var dateNow = new Date();

var seconds = Math.floor((dateFuture - (dateNow))/1000);
var minutes = Math.floor(seconds/60);
var hours = Math.floor(minutes/60);
var days = Math.floor(hours/24);

hours = hours-(days*24);
minutes = minutes-(days*24*60)-(hours*60);
seconds = seconds-(days*24*60*60)-(hours*60*60)-(minutes*60);

Solution 3:

I call it the "snowman ☃ method" and I think it's a little more flexible when you need additional timespans like weeks, moths, years, centuries... and don't want too much repetitive code:

var d = Math.abs(date_future - date_now) / 1000;                           // delta
var r = {};                                                                // result
var s = {                                                                  // structure
    year: 31536000,
    month: 2592000,
    week: 604800, // uncomment row to ignore
    day: 86400,   // feel free to add your own row
    hour: 3600,
    minute: 60,
    second: 1
};

Object.keys(s).forEach(function(key){
    r[key] = Math.floor(d / s[key]);
    d -= r[key] * s[key];
});

// for example: {year:0,month:0,week:1,day:2,hour:34,minute:56,second:7}
console.log(r);

Have a FIDDLE / ES6 Version (2018) / TypeScript Version (2019)

^{Inspired by Alnitak's answer.}