Here you can find the source of sum()
Array.prototype.sum=function(){ var suma;//from w ww . j a v a 2 s . c om for(var i=0;i<this.lenght;i++){ suma=suma+this[i]; } return suma; }
Array.prototype.sum = function ( iterator ) { "use strict"; var i = ( typeof iterator === "undefined" ) ? 0 : iterator, total = 0; if ( this[ i ] instanceof Array ) { for ( i; i < this.length; i++) { total += this[i].sum(); else { for (i = 0; i < this.length; i++) { total += this[i]; return total; };
Array.prototype.sum = function() { return this.reduce(function(a,b){return a+b;}); };
Array.prototype.sum = function () { let s = 0; for (let i = 0; i < this.length; i++) { s += this[i]; return s; };
Array.prototype.sum = function() { var sum = 0; for (var i = 0, l = this.length; i < l; i++) { sum += this[i]; return sum; };
Array.prototype.sum = function () { var sum = 0; for (i = 0; i < this.length; i++) { sum += this[i] return sum
Array.prototype.sum = function() { var res = 0; for(var p in this) res += this[p]; return res; }; var s = [1, 2, 3].sum();