how sort in js works code example

Example 1: javascript string array sort alphabetically

var items = ['réservé', 'premier', 'communiqué', 'café', 'adieu', 'éclair'];
items.sort((a, b) =>
   a.localeCompare(b)//using String.prototype.localCompare()
);

Example 2: sort arrays according to first array js

itemsArray.sort(function(a, b){  
  return sortingArr.indexOf(a) - sortingArr.indexOf(b);
});