Get the item that appears the most times in an array

Question

var store = [\'1\',\'2\',\'2\',\'3\',\'4\'];

I want to find out that 2 appear the most in the array. How do I go about doing that?

Answer 1

A fairly short solution.

function mostCommon(list) {
  var keyCounts = {};
  var topCount = 0;
  var topKey = {};
  list.forEach(function(item, val) {
    keyCounts[item] = keyCounts[item] + 1 || 1;
    if (keyCounts[item] > topCount) {
      topKey = item;
      topCount = keyCounts[item];
    }
  });

  return topKey;
}

document.write(mostCommon(['AA', 'AA', 'AB', 'AC']))