Inheriting from a C ++ class to JavaScript

I am using V8 in a C ++ program for extensions. I want to be able to create objects in JavaScript that "inherit" from a base class in C ++. This is a simple hierarchy in C ++:

class animal
{
public:
    void move();
    virtual void vocalize() = 0;
};

class cat : public animal
{
public:
    void vocalize() override;
    void ignore_owner();
};

      

        
        
        
      

    

This is cat

implemented in JavaScript instead of C ++:

function cat()
{
    this.vocalize = function() {}
    this.ignore_owner = function() {}
}

add_animal(new cat);

      

        
        
        
      

    

where add_animal()

is a global function implemented in C ++:

void add_animal(v8::Local<v8::Object> o);

      

        
        
        
      

    

In add_animal()

I manually add a property move

pointing to C ++ and make sure the property vocalize

exists and is a function.

var c = new cat;

c.ignore_owner();   // JavaScript code
c.move();           // error, undefined

add_animal(c);

c.move();           // okay, C++ code

      

        
        
        
      

    

My experience with JavaScript outside of web pages is limited. Does this circuit make sense? The fact that is add_animal()

used for both add the "base class" properties and add the animal to the list. counter-intuitive to me. I could add a second function:

var c = new cat;
make_animal(c);
add_animal(c);

      

        
        
        
      

    

but it takes discipline and looks confusing.

I could as well open animal

, use it to create objects, and add the cat

-specific properties:

function make_cat(c)
{
    c.vocalize = function() {}
    c.ignore_owner = function() {}
}

var c = new animal;
make_cat(c);

add_animal(c);

      

        
        
        
      

    

but it looks strange to me.

What is the best way to "inherit" from a C ++ class?