CountingSort.js

var CountingSort = function(A,k) {

    var B=[];
    B.push(null); // avoid undefined
    var C=[];
    for (var i=0;i<=k;i++){
        C[i] = 0;
    }
    for(var j=1;j<A.length;j++) {
        C[A[j]]++;
    }
    for(var i=1;i<=k;i++) {
        C[i]=C[i]+C[i-1];
    }
    for(var j=A.length-1;j>0;j--) {
        B[C[A[j]]] = A[j];
        C[A[j]]--;
    }
 
    return B;
};


var arr = [null,7,3,1,4,9,5,2,8];
var k = Math.max.apply(this, arr);
console.log(CountingSort(arr,k));