0

What I would like to have is something like this:

var fnc = new constructor(); // --> function()...
fnc(); // --> Running main function
fnc.method(); // --> Running method

So that one could create new fnc instances, while having the methods in the constructors prototype. However, I don't seem to be able to have result of the constructor as a function, as regardless of the return clause, it seems to become a object, resulting to ..

Uncaught TypeError: Property 'fnc' of object [object Object] is not a function

:(

Edit: Added example code. So what I'm thinking is along these lines.

var constructor = function() { return function() { console.log('Running main function.') }; };
constructor.prototype.method = function() { console.log('Running method.'); }

var fnc = new constructor();

console.log('constructor: ', constructor);
console.log('fnc:         ', fnc);
console.log('fnc.method:  ', typeof $.method);
console.log('');
fnc();
fnc.method();

In this case, one gets the... 

Uncaught TypeError: Object function () { console.log('Running main function.') } has no method 'method'

...error as the function provided by the constructor is different than the constructor itself, on which prototype chain is tacked on. Just can't seem to wrap my head around this. Did one version with jQuery like initialization, which did the trick alright but I later on found out that it ended up doing it through the empty function prototype, meaning every function got the methods.

crappish
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  • Can you show the implementation code you have so far? The three lines only show how you *want* it to behave, not how you've made it behave so far. – apsillers Aug 15 '13 at 13:02
  • Show us your code that is throwing this error. `fnc` is not a property in what you presented us. – Bergi Aug 15 '13 at 13:10

3 Answers3

2

You can not create callable objects from constructor function instances.

You could have a function that returns a callable function that has methods assigned to it:

function foo() {
    function fn() {
        ..do stuff..
    }
    fn.method = function () {
        ..do more stuff..
    };
    return fn;
}
var bar = foo();
bar(); //does stuff
bar.method(); //does more stuff

You could even call the function as a constructor, but it would actually be doing the same thing as calling the function directly as a function, and not be constructing a new instance of the class:

var baz = new foo();
baz(); //does stuff
baz.method(); //does more stuff
baz instanceof foo; //false
zzzzBov
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  • Yes, that's one way of doing but it doesn't use prototyping, meaning every new `fnc` would create their own functions instead of using the ones up the prototype chain. When you have lot of methods, lot of `fnc`'s and a low end device, it's not ideal. :/ – crappish Aug 16 '13 at 07:06
-2
function Constructor(n,s,r) {
this.var1 = n;
this.var2 = s;
this.var3 = r;
}

var fnc = new Constructor("Hi", 3, 6);

fnc.prototype.myMethod = function() {
console.log (this.var1);
}
C.A. Vuyk
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-2

You can create methods specifically to objects like this 

function myObject(name)
{
   this.name = name;
}

myObject.prototype =
{
   getName: function()
   {
      console.log("Name is: " + this.name);
      return this.name;
   }
}

var newObj = myObject("javascript");
var objname = newObj.getName();
console.log("Name is again: " + objname);
arielf
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