classmaker

ClassMaker

This module allows you to implement inheritance for your classes.

At first get a module instance:

var ClassMaker = require("ClassMaker");

ClassMaker has only one method: extend. This method takes object as the parameter; its fields and methods will be added to the new class-hier.

var HeirClass = ClassMaker.extend(parentObject);

Note: The extend method generates and returns a new class with all properties of an object that called the extend method and all properties of the parent object. It does not change the parent object or the class.

Let's show how it works. First we describe an Animal class constructor:

function Animal(name) {

    this.name = name||"Undefined Animal";
    this.getAbility = function () {
        return "I can run";
    };
    this.whoAreYou = function () {
        return "I am " + this.name + ", " + this.getAbility()
    }
}

And now we create a class-heir Dog:

var Dog = ClassMaker.extend(new Animal("Dog"));

Please note, we have created an instance of the Animal class. Now we can create an instance of the Dog class. Let's do this and call method whoAreYou

var Dog = ClassMaker.extend(new Animal("Dog"));
var dog = new Dog;
console.log(dog.whoAreYou());

> I am Dog, I can run

Now let's extend the Animal class and create a Duck class. For this purpose, we describe a bird object which extends the Duck class.

var bird = {
    ability: "fly",
    getAbility: function () {
        return "I can "+ this.ability;
    }
};

var Duck = ClassMaker.extend(new Animal("Duck"));
Duck = Duck.extend(bird);

var duck = new Duck;
console.log(duck.whoAreYou());

> I am Duck, I can fly

We have added properties of the bird object to properties of the Duck class and overrode the Duck class. We have added an ability field and overrode (hidden) parent method getAbility of the Duck class.

Note: The following code does not change the Duck class:

Duck.extend(bird);

The extend method returns a new class! It does not change the current class or the parent object!

But what should we do if we need to call the parent method? Let's see an example.

var SwimDuck = Duck.extend({
    whoAreYou: function() {
        return this._super()+ ", and swim"; // parent
    }
});
swimDuck  = new SwimDuck();
console.log(swimDuck.whoAreYou());

> I am Duck, I can fly, and swim

So, all of your parent methods are stored and you can call them using method _super() into the method body.

Good Luck!