CODEWITHSUNDEEP
javascript
dSquared
dSquared

Reputation: 9825

How to round to nearest hour using JavaScript Date Object

I am working on a project that requires a time in the future to be set using the Date object.

For example:

futureTime = new Date();
futureTime.setHours(futureTime.getHours()+2);

My questions is; once the future date is set, how can I round to the closest full hour and then set the futureTime var with it?

For example:

Given 8:55 => var futureTime = 9:00
Given 16:23 => var futureTime = 16:00

Any help would be appreciated!

Upvotes: 50

Views: 64089

Answers (7)

Sebastian
Sebastian

Reputation: 483

As a matter of fact Javascript does this default which gives wrong time.

let dateutc="2022-02-17T07:20:00.000Z";
let bd = new Date(dateutc);
console.log(bd.getHours()); // gives me 8!!!!!

it is even wrong for my local time because I am GMT+2 so it should say 9. moment.js also does it wrong so you need to be VERY carefull

Upvotes: 0

Felix Livni
Felix Livni

Reputation: 1244

The other answers ignore seconds and milliseconds components of the date.

The accepted answer has been updated to handle milliseconds, but it still does not handle daylight savings time properly.

I would do something like this:

function roundToHour(date) {
  p = 60 * 60 * 1000; // milliseconds in an hour
  return new Date(Math.round(date.getTime() / p ) * p);
}

var date = new Date(2011,1,1,4,55); // 4:55
roundToHour(date); // 5:00

date = new Date(2011,1,1,4,25); // 4:25
roundToHour(date); // 4:00

Upvotes: 36

Shubham Rai
Shubham Rai

Reputation: 39

Pass any cycle you want in milliseconds to get next cycle example 1 hours

function calculateNextCycle(interval) {
    const timeStampCurrentOrOldDate = Date.now();
    const timeStampStartOfDay = new Date().setHours(0, 0, 0, 0);
    const timeDiff = timeStampCurrentOrOldDate - timeStampStartOfDay;
    const mod = Math.ceil(timeDiff / interval);
    return new Date(timeStampStartOfDay + (mod * interval));
}

console.log(calculateNextCycle(1 * 60 * 60 * 1000)); // 1 hours in milliseconds

Upvotes: -1

Joe
Joe

Reputation: 82634

Round the minutes and then clear the minutes:

var date = new Date(2011,1,1,4,55); // 4:55
roundMinutes(date); // 5:00

function roundMinutes(date) {

    date.setHours(date.getHours() + Math.round(date.getMinutes()/60));
    date.setMinutes(0, 0, 0); // Resets also seconds and milliseconds

    return date;
}

Upvotes: 60

rlemon
rlemon

Reputation: 17667

Or you could mix the two for optimal size. http://jsfiddle.net/HkEZ7/

function roundMinutes(date) {
    return date.getMinutes() >= 30 ? date.getHours() + 1 : date.getHours();
}

Upvotes: 3

HBP
HBP

Reputation: 16043

A slightly simpler way :

var d = new Date();
d.setMinutes (d.getMinutes() + 30);
d.setMinutes (0);

Upvotes: 23

JamesHalsall
JamesHalsall

Reputation: 13495

Another solution, which is no where near as graceful as IAbstractDownvoteFactory's

var d = new Date();
if(d.getMinutes() >= 30) {
   d.setHours(d.getHours() + 1);
}
d.setMinutes(0);

Upvotes: 4

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