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

Question

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.

    Array.method('reduce',function(f,value){
      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);

    console.log(result);

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

Morgoth · Accepted Answer · 2019-07-23 08:39:12Z

3

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:

http://jsfiddle.net/x2ydm091/2/

Array.prototype.reduce=function(f, value){
    for(var i=0;i< this.length;i++){
        value=f(this[i],value);
    }
    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);
alert(result);

Hope that helps!

edited Jul 23, 2019 at 8:39

Morgoth

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answered Jan 12, 2015 at 7:51

Rakesh_Kumar

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4 Comments

Abhi Dhadve Over a year ago

Thanks for your answer and it is working. But i am still confused with why Array.method() is not working as douglas crockford used this example to explain augmenting Array.prototype.

Ginden Over a year ago

Array.method doesn't exist and didn't.

Rakesh_Kumar Over a year ago

@AbhiDhadve This link will clear your doubts.. stackoverflow.com/questions/3966936/… . Also if mine answer helped you, accept it as answer.. ;)

Abhi Dhadve Over a year ago

Here is the actual solution that @Rakesh_Kumar provided. First we have to add it to Function.prototype . Function.prototype.method = function (name, func) { this.prototype[name] = func; return this; };

viery365 · Accepted Answer · 2016-07-23 10:37:32Z

-1

I am reading the book as well and I I think this does not work because before in the book he defined a method called method to avoid the use of Array.prototype.something, or Function.prototype something everytime you want to add methods to array, function or objects prototypes.

answered Jul 23, 2016 at 10:37

viery365

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Comments

R.A. · Accepted Answer · 2017-05-02 03:36:09Z

-1

Function.prototype.method = function(name, func) {
this.prototype[name] = func;
return this;
};

Append the above code at the beginning. I had the same problem. They have mentioned this in Preface. Check it out.... I hope it helps.... :)

answered May 2, 2017 at 3:36

R.A.

1

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