Javascript Order Objects by Average Rank

gistfile1.txt

function orderByRank(array) {
  var arrayCopy = array.slice(); // if we don't want to modify org array

  arrayCopy.sort(function(a, b) {
    return a.ranking - b.ranking;
  });

  return arrayCopy;
}

function avgRank(array) {
    return array.reduce(function(prev, crr) { return (prev.ranking || prev) + crr.ranking; }, 0) / array.length;

}

var array = [
  {
    name: 'ala',
    ranking: 2
  },
  {
    name: 'ma',
    ranking: 15
  },
  {
    name: 'kota',
    ranking: 1
  }
];

console.log('orderByRank: ' + JSON.stringify(orderByRank(array)));
console.log('avgRank: ' + JSON.stringify(avgRank([])));