Abhi Dhadve Abhi Dhadve - 1 year ago 74
Javascript Question

Adding Methods to array prototype so i can apply it to array object.But it is giving an error TypeError: Array.method is not a function

I am trying add a method to Array prototype.But it is giving me an error TypeError: Array.method is not a function

I am trying this example from JavaScript: The Good Parts.

Here is a piece of my code.

var i;
for(i=0; i < this.length; i+1){
value = f(this[i],value);
return value;

var data = [1,3,2,4,5,6,7,8,9];

var add = function(value1, value2){
return value1 + value2;

var result = data.reduce(add, 0);


I want to apply the reduce method to data array. So i can do addition ,multiplication on array and return the result.

Answer Source

Most of the code you have tried is correct. I think you are trying to add all the elements and return using reduce function to array. But to achieve what you wanted,checkout fiddle link:


  Array.prototype.reduce=function(f, value){
                            for(var i=0;i< this.length;i++){
                          return value;

  var add = function(a,b){
              return a+b;

  var data = [1,3,2,4,5,6,7,8,9];
  var result = data.reduce(add,0);

Hope that helps!

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