Interview question.

chaser.js

// Order by rank function
function orderByRank(arr) {  
  return arr.sort(function(a, b) {
     return a.rank > b.rank;
  });
}

//Average ranking function
function avgRanking(arr) {
	var total = arr.reduce(function(total, next) {
  	total = total + next.rank;
    return total;
  }, 0);
  
  return total / arr.length;
}