Should I differentiate object types by calling methods via variables?

I have three JavaScript objects. The first one serves merely as a prototype. The other two are implementation of a specific type.

var MainPrototype = {};
var SpecificType = $.extend(Object.create(MainPrototype));
var OtherSpecificType = $.extend(Object.create(MainPrototype));

I am missing the option of a parent-method and am trying to implement some specifics for each specific type.

I started of by comparing the types within the main prototype object, yet I found the nesting if-else clausing worrysome and in case that new types would be introduced, I guess the code will get ugly fast. I also does not feel right to put the specifics into the main function.

var MainPrototype = {
    function: bind() {
        //generic stuff

        if (this.type === SpecificType.type) {
          // specifics for this type
        } else if (this.type === OtherSpecificType.type) {
          // specifics for other type
        }
    }
}

That's why I thought I could call a specific function dynamically.

var MainPrototype = {
    bind: function() {
        //generic stuff
        var specificBindMethod = this.type + "Bind";
        if (typeof(this[bindMethod]) === "function") {
            this[categoryBindMethod]();
        }
    }
};

var SpecificType = $.extend(Object.create(MainPrototype, {
  type: 'specific',
  specificBind: function() {
    // doSpecifics
  }
});
var OtherSpecificType = $.extend(Object.create(MainPrototype, {
  function: 'other',
  otherBind: function() {
    // doSpecifics
  }
})

Now I can define the specific function within its proper object and only if they exist they will get called getting rid of the nesting.

I am wondering if this approach is better in terms of maintainability and extensibility or if I should have stayed with the if-else-approach or if there is anything better to solve my current use case.

Why wouldn't you create a method with a unique name accross all subclasses? In this way you don't have to generically build a function name, which can be a pain to maintain code / refactor

For instance :

var MainPrototype = {
    bind: function() {
        //generic stuff
        if (typeof(this.subBind) === "function") {
            this.subBind();
        }
    }
};

var SpecificType = $.extend(Object.create(MainPrototype, {
    type: 'specific',
    subBind: function() {
        // doSpecifics
    }
});
var OtherSpecificType = $.extend(Object.create(MainPrototype, {
    function: 'other',
    subBind: function() {
        // doSpecifics
    }
})

StackExchange Code Review Q#47145, answer score: 4