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192

Check if a date is tomorrow or the day after tomorrow

rated 0 times [ 198] [ 6] / answers: 1 / hits: 16904 / 9 Years ago, fri, april 24, 2015, 12:00:00

I'm looking for a way to get tomorrow and the day after tomorrow returned from a function that receives to dates:

The current date:

2015/04/24 18:15:00

The date in the future:

2015/04/25 02:40:00

The function should return tomorrow here. I tried looking up some functions but they all return 0 not 1.

function days_between(date1, date2) {



    // The number of milliseconds in one day

    var ONE_DAY = 1000 * 60 * 60 * 24



    // Convert both dates to milliseconds

    var date1_ms = date1.getTime()

    var date2_ms = date2.getTime()



    // Calculate the difference in milliseconds

    var difference_ms = Math.abs(date1_ms - date2_ms)



    // Convert back to days and return

    return Math.round(difference_ms/ONE_DAY)



}

Any ideas?

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vaughns

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4 Years ago

answered 9 Years ago zahrafrancisr · Accepted Answer

First, here's the documentation on the Javascript Date object and its prototype.

So, how can you determine if a particular day (date2) is one day after another (date1)? Well, add one day to date1 and see if the dates match:

var date1_tomorrow = new Date(date1.getFullYear(), date1.getMonth(), date1.getDate() + 1);

if (date1_tomorrow.getFullYear() == date2.getFullYear() && date1_tomorrow.getMonth() == date2.getMonth() && date1_tomorrow.getDate() == date2.getDate()) {

    return tomorrow; // date2 is one day after date1.

}

If you want to determine if date2 is two days after date1, you can use the same logic as above but add 2 days instead of 1:

var date1_overmorrow = new Date(date1.getFullYear(), date1.getMonth(), date1.getDate() + 2);

if (date1_overmorrow.getFullYear() == date2.getFullYear() && date1_overmorrow.getMonth() == date2.getMonth() && date1_overmorrow.getDate() == date2.getDate()) {

    return the day after tomorrow; // date2 is two days after date1.

}

If the dates are not 1 or 2 days apart, the final bit would be to just return the date in your desired format:

return date2.toLocaleString(); // Firefox 29+, Chrome 24+, IE 11+

// OR

return date2.getFullYear() + '/' + (date2.getMonth() + 1) + '/' + date2.getDate() + ' ' + date2.getHours() + ':' + date2.getMinutes() + ':' + date2.getSeconds(); // Et al.

Test

function incrementDate(date, n) {

  return new Date(date.getFullYear(), date.getMonth(), date.getDate() + n);

}



function compareDates(date1, date2) {

  return date1.getFullYear() == date2.getFullYear() && date1.getMonth() == date2.getMonth() && date1.getDate() == date2.getDate();

}



function formatDate(date) {

  var year = date.getFullYear();

  var month = date.getMonth() + 1;

  var day = date.getDate();

  return year + '-' + (month < 10 ? '0' : '') + month + '-' + (day < 10 ? '0' : '') + day;

}



$(function() {

  var $output = $('#output');

  

  var comparisons = [

    {'start': new Date(2016, 6 - 1, 1), 'inc': 1, 'target': new Date(2016, 6 - 1, 2)},

    {'start': new Date(2016, 6 - 1, 30), 'inc': 1, 'target': new Date(2016, 7 - 1, 1)},

    {'start': new Date(2016, 12 - 1, 31), 'inc': 1, 'target': new Date(2017, 1 - 1, 1)}

  ];

  for (var i = 0, len = comparisons.length; i < len; i += 1) {

    var comp = comparisons[i];

    var $row = $('<tr>');

    

    $('<td>').text(formatDate(comp.start)).appendTo($row);

    $('<td>').text(comp.inc).appendTo($row);

    $('<td>').text(formatDate(comp.target)).appendTo($row);

    $('<td>').text(compareDates(comp.target, incrementDate(comp.start, comp.inc)) ? 'yes' : 'no').appendTo($row);

    

    $output.append($row);

  }

});

<script src=https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js></script>

<table>

  <thead>

    <tr>

      <th>Start</th>

      <th>Inc</th>

      <th>Target</th>

      <th>Equal</th>

    </tr>

  </thead>

  <tbody id=output>

  </tbody>

</table>