Question

I am reading the book “Javascript: The good parts”.
Now I am reading chapter about Augmenting Types:

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

UPDATE:
Why following code does not work?

js> Function.prototype.method("test", function(){print("TEST")});
typein:2: TypeError: this.prototype is undefined

But following code works without problems:

js> Function.method("test", function(){print("TEST")});
function Function() {[native code]}

Why this code works?

js> var obj = {"status" : "ST"};
js> typeof obj;
"object"
js> obj.method = function(){print(this.status)};
(function () {print(this.status);})
js> obj.method();
ST

“obj” is object.
But I can call method “method” on it.
What is the difference between Function.prototype.method and obj.method?

Answer 1

this refers to Function.prototype because you called .method on that. So, you’re using Function.prototype.prototype which does not exist.

Either use Function.method(...) or this[name] = ... to eliminate one of the .prototypes.