Nodejs Utililty Methods Array Sum

Array.prototype.sum = function() {
  total = 0;
  for (var i=0;i < this.length;i++) {
    total += this[i];
  return total;
};
  var a = [];
  for (var i=0;i < 1000;i++) {
...

var ary1 = new Array(12, 55, 43, 32, 44);
var ary2 = new Array(12, 33, 1);
Array.prototype.sum = function() {
    var output = 0;
    for (var i = 0; i < this.length; i++) {
        output += this[i];
    return output;
};
...

Array.prototype.sum = function(){
  var sum = 0;
  for(var index in this){
    if(typeof this[index] === "number"){
      sum += this[index];
  return sum;
var numbers = [1,2,3,4,5];
console.log(numbers.sum());

Array.prototype.sum = function(){
  var sum = 0;
  for(var i = 0; i < this.length; i++){
    if(typeof this[i] === "number"){
      sum += this[i];
  return sum;
var numbers = [1,2,3,4,5];
console.log(numbers.sum());

var ary1 = new Array(12, 55, 43, 32, 44);
var ary2 = new Array(12, 33, 1);
Array.prototype.sum = function() {
    var output = 0;
    for (var i = 0; i < this.length; i++) {
        output += this[i];
    return output;
};
...

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

Array.prototype.sum = function () {
  return this.reduce(function(sum, val){ 
    return sum + val
  })
console.log([1, 2, 3, 4].sum());

Array.prototype.sum = function() {
  return this.reduce((result, element) => result + element, 0);
};

function range(a, b) {
    return [...Array(b-a).keys()].map(x => x + a);
Array.prototype.sum = function() {
    return this.reduce((a, b) => a + b, 0);
module.exports = function(n) {
    var sumOfSquares = range(1,101).map(x => x*x).sum();
    var squareOfSum = Math.pow(range(1,101).sum(), 2);
...

Array.prototype.sum = function() {
  return this.reduce(function(p, c, i, arr) {
    return p + c;
  });
};
var a = [];
process.stdin.resume();
process.stdin.setEncoding("utf8");
process.stdin.on("data", getNum);
...