Nodejs Array Sum sum(selectorfun)

Method Source Code

/**//from w ww  .j  a  va 2  s.co  m
 * Return the sum of all the values in the array. If selectorfun is given,
 * it will be called to retrieve the relevant value for each item in the
 * array.
 */
Array.prototype.sum = function(selectorfun)
{
  if (selectorfun)
  {
    return this.map(selectorfun).sum();
  }
  else
  {
    var ret = 0;
    this.forEach(function(e) { ret += e });
    return ret
  }
};

Array.prototype.unique = function()
{
  return this.reduce(function(list, e)
  {
    if (list.indexOf(e) == -1)
      list.push(e);

    return list;
  }, []);
}

Array.prototype.__defineGetter__("last", function()
{
   return this[this.length - 1];
});

Array.prototype.__defineSetter__("last", function() {});

Array.prototype.extend = function(list)
{
  this.push.apply(this, list);
  return this;
};

Array.prototype.insert = function(index, list, replace_count)
{
  this.splice.apply(this, [index, replace_count || 0].extend(list));
  return this;
};

Array.prototype.contains = function(str)
{
  return this.indexOf(str) != -1;
};

Related

1. sum(fun)

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

2. 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) {
   ...
   

3. 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;
   };
   

4. sum(s)

   Array.prototype.sum = function (s) {
     s = s || Selector;
     var l = this.length;
     var sum = 0;
     while (l-- > 0) sum += s(this[l]);
     return sum;
   };
   

5. 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]);
   ...
   

6. sum(xAndY)

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

7. 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());
   

8. sumItems()

   Array.prototype.sumItems = function(){
     var sum = 0;
     for(var i=0; i<this.length; i++){
       sum=sum+this[i];
     return(sum);
   var arr = new Array;
   arr = [5,10];
   ...