Question

I am trying to extend an object, and I want to modify a method of the first, not to override it. I don’t think this is clear so here is an example:

var object1 = {
    whatever : function(){
        console.log('first object method');
    }
}

var object2 = {
    whatever : function(){
        console.log('second object method');
    }
}

var object = $.extend(true, object1, object2);

object.whatever();

This example will output second object method, but what I want is that it ouput first object method and second object method.

Is there a way to do this?

Answer 1

Javascript uses prototypal inheritance, so you can make object2 inherit object1’s properties and methods by doing

object2.prototype=object1;

this means that object2 will inherit all the properties and methods of object1, and any overwritten methods can be accessed at object2.prototype.method()

so parent::whatever(); is equivalent to this.prototype.whatever(); when calling from the scope of object2.

---

var object1 = {
    whatever : function(){
        console.log('first object method');
    }
}

var object2 = {
    whatever : function(){
        console.log('second object method');
        this.prototype.whatever(); // Equivalent to parent::whatever(); 
    }
}

object2.prototype=object1; // Makes object2 inherit object1's properties and methods

object2.whatever(); // "second object method" "first object method"