Nodejs Array Sum sum(s)

Method Source Code

Array.prototype.sum = function (s) {
   s = s || Selector;//  ww  w  . j  a  v a 2  s . c  om
   var l = this.length;
   var sum = 0;
   while (l-- > 0) sum += s(this[l]);
   return sum;
};

Related

1. sum(array)

   Array.prototype.sum = function(array) { 
       return this.reduce(function(a,b) { 
           return a + b 
       }) 
   

2. sum(begin, end)

   Array.prototype.sum = function(begin, end) {
     var total = 0;
     for (var i = begin >> 0 || 0, len = end + 1 >> 0 || this.length >> 0; i < len; i++) {
       total += +this[i] || 0;
     return total;
   };
   

3. sum(fun)

   Array.prototype.sum = function (fun) {
       var result = 0;
       this.forEach(x => result += fun ? fun(x) : x);
       return result;
   };
   

4. sum(func)

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

5. sum(prop)

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

6. sum(selector)

   Array.prototype.sum = function(selector) {
       if (typeof selector !== 'function') {
           selector = function(item) {
               return item;
       var sum = 0;
       for (var i = 0; i < this.length; i++) {
           sum += selector(this[i]);
   ...
   

7. sum(selectorfun)

   Array.prototype.sum = function(selectorfun)
     if (selectorfun)
       return this.map(selectorfun).sum();
     else
       var ret = 0;
   ...
   

8. sum(xAndY)

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

9. sumArrayItems()

   Array.prototype.sumArrayItems = function() {
     var countIndex = this.length - 1;
     var sum =0;
     while ( countIndex >= 0) {
       sum = sum + this[ countIndex ];
       countIndex--;
     return sum;
   var findMissing = function( arr1 , arr2 ) {
     return Math.abs( arr1 - arr2);
   findMissing([1,2].sumArrayItems() , [1,2,5].sumArrayItems());