Check if date string is greater than 3 days

Question

I need some help with a javascript code, I need to check two string date values (first date and second date) if the second date is greater than 3 days, I'm getting the values in string format mm/dd/yyyy. Please help.

var firstDate = '10/01/2019'
var secondDate = '10/04/2019'

if ((inputData.firstDate) + 3 === inputData.secondDate) {
  return {
    dateCheck: 'Not greater than 3 days'
  };
} else {
  return {
    dateCheck: 'Greater than 3 days'
  };
}

Answer 1

To add N days to a Date you use Date.getDate() + N

var d1 = new Date('10/01/2019');
var d2 = new Date('10/04/2019');
var isGreater = +d2 > d1.setDate(d1.getDate() + 3); // false (equals three days)

Given the above you can make a simple reusable function

/**
 * Check if d2 is greater than d1
 * @param {String|Object} d1 Datestring or Date object
 * @param {String|Object} d2 Datestring or Date object
 * @param {Number} days Optional number of days to add to d1
 */
function isDateGreater (d1, d2, days) {
  d1 = new Date(d1);
  return +new Date(d2) > d1.setDate(d1.getDate() + (days||0))
}

console.log(isDateGreater('10/01/2019', '10/03/2019', 3)); // false (smaller)
console.log(isDateGreater('10/01/2019', '10/04/2019', 3)); // false (equal)
console.log(isDateGreater('10/01/2019', '10/05/2019', 3)); // true (greater than)
// Without the optional third parameter
console.log(isDateGreater('10/01/2019', '10/05/2019')); // true (is greater date)

To recap: make a function that, after adding N days to a date, evaluates two timestamps.

Date.setDate ^_MDN
Date.getDate ^_MDN

Answer 2

For so many different Date usage I recommend using dateFns. DateFns is date object JS library having many different available methods for date manipulation. Reference : DateFns

You can also format dates in different format using format from library

For this I recommend addDays method from dateFns

const secondDate = '04/04/2019',
firstDate = '04/01/2019'

alert(new Date(secondDate) >= dateFns.addDays(new Date(firstDate), 3))

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/date-fns/1.30.1/date_fns.min.js"></script>

Answer 3

I have enclosed it inside a function so you can test.

Here we are checking if ((date1 - date2) < 259200000) (3 Days in Unix timestamp)

function isItGreaterThan(date1, date2, days) {
  var firstDate = new Date(date1);
  var secondDate = new Date(date2);
  var time = days * 60 * 60 * 24 * 1000
  if ((secondDate.getTime() - firstDate.getTime()) < time) {
    console.log({dateCheck: `Not greater than ${days} days`});
  } else {
    console.log({dateCheck: `Greater than ${days} days`});
  }
}

isItGreaterThan('10/01/2019', '10/02/2019', 3);
isItGreaterThan('10/01/2019', '10/03/2019', 3);
isItGreaterThan('10/01/2019', '10/04/2019', 3);

isItGreaterThan('10/01/2019', '10/02/2019', 10);
isItGreaterThan('10/01/2019', '10/03/2019', 10);
isItGreaterThan('10/01/2019', '10/14/2019', 10);