Round moment.js object time to nearest 30 minute interval

I was trying to round the moment.js time object to next nearest 30 minute interval. But looks my logic us wrong.

Ex:

10:13am -> 10:30am
11:45am -> 12:00pm

Here is my current code

start = moment();
minuteReminder = start.minute() % 30;
start.add(minuteReminder, 'minutes');
start.format("D YYYY, h:mm:ss a");

Edit 2021 : easiest solution

const start = moment('2018-12-08 09:42');
const remainder = 30 - (start.minute() % 30);
 
const dateTime = moment(start).add(remainder, "minutes").format("DD.MM.YYYY, h:mm:ss a");

console.log(dateTime);

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.20.1/moment.min.js"></script>

Million ways to do this. You don't need moment.js really. Anyway, here is one.

Based on @Volune and @Cabloo answers and comments, an updated version can look like:

function round(date, duration, method) {
    return moment(Math[method]((+date) / (+duration)) * (+duration)); 
}

Which then can be used like:

var date = moment();
var roundedDate = round(date, moment.duration(15, "minutes"), "ceil");

A generic solution:

var ROUNDING = 30 * 60 * 1000; /*ms*/
start = moment();
start = moment(Math.ceil((+start) / ROUNDING) * ROUNDING);
start.format("D YYYY, h:mm:ss a");

You can change ROUNDING from 30 minutes to whatever you want, and change Math.ceil by Math.round or Math.floor if you want another way to round the value.

You can do it by a simple if-else clause:

if(moment().minute()> 30){
    var myTime = moment().minute(30).second(0);
} else {
    var myTime = moment().minute(0).second(0);
}

You could do it with two ifs:

// Current date
let now = moment();

// Getting hour and minute
let hour   = now.hour();
let minute = now.minute();

// Rounding minute on 30 mins interval
if(minute <= 30) now.set({minute: 30});
if(minute >  30) now.set({hour: hour + 1, minute: 0});

even though the question has been answered, I'd like to share my solution too.

var moment = require('moment');

const roundToNearestXXMinutes = (start, roundTo) => {
    let remainder = roundTo - (start.minute()+ start.second()/60) % roundTo;
    
    remainder = (remainder >  roundTo/2) ? remainder = -roundTo + remainder : remainder;
    const changedDate = moment(start).add(remainder, "minutes" ).seconds(0).format("DD.MM.YYYY HH:mm:ss");    
}

roundToNearestXXMinutes(moment(), 15);

EDIT: Thanks to Ishmael Sibisi for pointing to a flaw in my code! :)

For my case, I instead wanted something like

04-28-2021 20:00 => 04-28-2021 20:00
04-28-2021 20:30 => 04-28-2021 20:30
04-28-2021 20:11 => 04-28-2021 20:00
04-28-2021 20:35 => 04-28-2021 20:30

so the function below did the trick

function toNearest30Minutes(date) {
  const start = moment(date)
  let remainder: number
  const elapse = start.minute() % 30
  if (elapse === 0) {
    return moment(date).format()
  } else {
    remainder = 30 - elapse
    return moment(start).add(remainder, "minutes").format()
  }
}

The function above is just an adaptation of @jtromans answer higher above

One-line solution

 moment().add( moment().minute() > 30 && 1 , 'hours').minutes( moment().minute() <= 30 ? 30 : 0).format("hh:mm a")

Working exemple :

var min = moment().minute()
var dateTime = moment().add(min > 30 && 1 , 'hours').minutes(min <= 30 ? 30 : 0).format("hh:mm a")

console.log(dateTime);

<script src="https://cdnjs.cloudflare.com/ajax/libs/moment.js/2.20.1/moment.min.js"></script>

the code below rounds up the current time to the nearest 30 minutes and also flawlessly takes care of any trailing seconds

    var moment = require('moment')
    var main = Date.now() //2020-03-13T23:17:34+01:00
    var mainFormat = moment(main)
    var secs = mainFormat.second()
    var justMinutes = mainFormat.subtract(secs, 'seconds')
    var remainder = 30 - (justMinutes.minute() % 30);
    var dateTime = moment(justMinutes).add(remainder, 'minutes')
    var final = dateTime.format()
    console.log(final) 
    //2020-03-13T23:20:00+01:00