Javascript inheritance and function overriding

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// Base state class -------------------------
function StateConstuctor()
{

}

// Inherited learn class --------------------
function StateLearnConstructor()
{

}

// Inherited exam class ---------------------
function StateExamConstructor()
{

}


function extend(Child, Parent)
{
    var F = function() { }
    F.prototype = Parent.prototype
    Child.prototype = new F()
    Child.prototype.constructor = Child
    Child.superclass = Parent.prototype
}


function createState(rollType)
{
    if (rollType == 'learn')
    {
        extend(StateLearnConstructor, StateConstuctor);
        var state = new StateLearnConstructor();

        return state;
    }
    else if (rollType == 'exam')
    {
        extend(StateExamConstructor, StateConstuctor);
        var state = new StateExamConstructor();

        return state;
    }
}

StateConstuctor.prototype.getTitles = function()
{
   console.log('base "virtual" function');
}
StateLearnConstructor.prototype.getTitles = function()
{
   console.log('learn');
}
StateExamConstructor.prototype.getTitles = function()
{
   console.log('exam');
}

Hello, I have the following "OOP" structure and I want to emulate something like virtual functions in C++. So I have base virtual function in StateConstructor and different realizations for each subclass.

var state = createState('exam');
state.getTitles();

But this code calls StateConstructor base virtual function. What's wrong here?

asked 23 secs ago

Ockonal

9,095

Javascript inheritance and function overriding