Sort array by date gives unexpected results

Question

This will sound as an easy problem but I spent my Sunday trying to figure out what\'s wrong with my implementation described below so I am posting it to SO as a last resort.

Answer 1

let sortedDates = dates.sort(function(a, b){
  return moment(b).format('X')-moment(a).format('X')
});

Since moment can format valid dates the best way is to use the sort method javascript, so when formatting the date to timestamp, basically you sort by number.

References:

http://www.momentjs.com/docs/#/displaying/format

http://www.w3schools.com/jsref/jsref_sort.asp