Sorting array of strings having year and month in JavaScript


Suppose, we have an array of Strings that contains month-year combined strings like this −

const arr = ["2009-feb", "2009-jan", "2010-mar", "2010-jan", "2011-jul",
"2011-sep", "2011-jan", "2012-jan", "2012-dec", "2012-feb", "2013-may",
"2013-jul", "2013-jun", "2014-jan", "2014-dec", "2014-may", "2015-may",
"2015-jan", "2015-jun", "2016-jan", "2016-dec"];

We are required to write a JavaScript function that takes in one such array and sorts these dates in oldest to latest order.

Example

The code for this will be −

const arr = ["2009-feb", "2009-jan", "2010-mar", "2010-jan", "2011-jul",
"2011-sep", "2011-jan", "2012-jan", "2012-dec", "2012-feb", "2013-may",
"2013-jul", "2013-jun", "2014-jan", "2014-dec", "2014-may", "2015-may",
"2015-jan", "2015-jun", "2016-jan", "2016-dec"];
const sorter = (a, b) => {
   const getDate = date => {
      let day = date.split('-');
      day[1] = {
         jan: 1, feb: 2, mar: 3, apr: 4, may: 5, jun: 6, jul: 7, aug: 8, sep: 9, oct: 10, nov: 11, dec: 12
      }
      [day[1]
      .substring(0, 3)
      .toLowerCase()] || 0;
      return day;
   }
   const aDate = getDate(a);
   const bDate = getDate(b);
   return aDate[0] - bDate[0] || aDate[1] - bDate[1];
}
arr.sort(sorter);
console.log(arr);

Output

And the output in the console will be −

[
   '2009-jan', '2009-feb',
   '2010-jan', '2010-mar',
   '2011-jan', '2011-jul',
   '2011-sep', '2012-jan',
   '2012-feb', '2012-dec',
   '2013-may', '2013-jun',
   '2013-jul', '2014-jan',
   '2014-may', '2014-dec',
   '2015-jan', '2015-may',
   '2015-jun', '2016-jan',
   '2016-dec'
]

Updated on: 21-Nov-2020

131 Views

Kickstart Your Career

Get certified by completing the course

Get Started
Advertisements