Nodejs Utililty Methods Array Sum

Array.prototype.sum = function(){
  var val = 0;
  this.forEach(function(v){
    val +=v;
  });
  return val;
};

Array.prototype.sum = function () {
    var total = 0;
    var i = this.length;
    while (i--) {
        total += this[i];
    return total;
function isEmpty(obj) {
...

Array.prototype.sum = function () {
  return this.reduce((sum, n) => sum + Number(n), 0)

Array.prototype.sum = function () {
  return this.reduce(function (total, aValue) {
    return total + Number(aValue);
  });
};

var log = console.log.bind(console)
Array.prototype.sum = function() {
    return this.reduce(function(previous, current) {
        return previous + current
    })
var numbers = [1, 2, 3, 4, 5, 6]
var result = numbers.sum()
log(result)
...

Array.prototype.sum=function(){
   return this.reduce(function(s,n){return s+n})

Array.prototype.sum = function()
    var sum = 0;
    for(var i = this.length; -- i >= 0 ;)
        sum += (this[i] === null || this[i] === undefined) ? 0 : this[i];
    return sum;

Array.prototype.sum = function() {
  for(var sum = i = 0; i < this.length; i++) {
    sum += this[i]
  return sum
var arr = [1,21,3,4,22,45,6,7,32];
console.log(arr.join("+")+"="+arr.sum());

Array.prototype.sum = function() {
  var i, sum;
  sum = 0;
  for (i=0; i<this.length; i++) {
    sum+=this[i];
  return sum;
};

Array.prototype.sum = function(){
  for (var i = 0, sum = 0 ; i != this.length; ++i) {
    var n = this[i];
    if(!isNaN(n)) {
      sum += n*1;
  return sum;
};
...