Here you can find the source of sum()
Array.prototype.sum = function(){ return this.reduce( (a,b) => a + b, 0) }
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; }; ...
Array.prototype.sum = function() { for (var sum = i = 0; i < this.length; i++) { sum += parseInt(this[i]) }; return sum
Array.prototype.sum = function(){ "use strict"; var count = 0; this.forEach(function(item){ count += item; }); return count; };
Array.prototype.sum = function(){ 'use strict'; var count = 0; this.forEach(function(item){ count += parseFloat(item) || 0; }); return count; };
Array.prototype.sum = function () { var sum, i; sum = 0; for (var i = 0; i < this.length; i++) { sum += this[i]; }; return sum; console.log([1, 3, 12, 33, 2].sum());