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' ]