# Factory

* Define an interface for creating an object, but let subclasses decide which class to instantiate. Factory Method lets a class defer instantiation to subclasses.
* loose coupling by eliminating the need to bind  application specific classes into code.
* It is just a fancy name for a method that instantiates an object.
* Its job is to create an object.
* **Real time EX:** Nescafe machine - press button to get the respective output.

![Factory Method](https://1698315463-files.gitbook.io/~/files/v0/b/gitbook-legacy-files/o/assets%2F-LiuzoHqHr4MUK1nJBO8%2F-LoZXXvpIA3kCvWyfEW4%2F-LoZtuSopiN4G078yI-R%2Fimage.png?alt=media\&token=fab32f21-3463-495f-8e84-013817b2a17e)

```javascript
EX:
var fromPrototype = function(prototype, object) {
    var newObject = Object.create(prototype);
    for (var prop in object) {
        if (object.hasOwnProperty(prop)) {
            newObject[prop] = object[prop];
        }
    }
  return newObject;
};

// Define the Pizza product
var Pizza = {
    description: 'Plain Generic Pizza'
};

// And the basic PizzaStore
var PizzaStore = {
    createPizza: function(type) {
        if (type == 'cheese') {
            return fromPrototype(Pizza, {
                description: 'Cheesy, Generic Pizza'
            });
        } else if (type == 'veggie') {
            return fromPrototype(Pizza, {
                description: 'Veggie, Generic Pizza'
            });
        }
    }
};

var ChicagoPizzaStore = fromPrototype(PizzaStore, {
    createPizza: function(type) {
        if (type == 'cheese') {
            return fromPrototype(Pizza, {
                description: 'Cheesy, Deep-dish Chicago Pizza'
            });
        } else if (type == 'veggie') {
            return fromPrototype(Pizza, {
                description: 'Veggie, Deep-dish Chicago Pizza'
            });
        }
    }
});

var CaliforniaPizzaStore = fromPrototype(PizzaStore, {
    createPizza: function(type) {
        if (type == 'cheese') {
            return fromPrototype(Pizza, {
                description: 'Cheesy, Tasty California Pizza'
            });
        } else if (type == 'veggie') {
            return fromPrototype(Pizza, {
                description: 'Veggie, Tasty California Pizza'
            });
        }
    }
});

// Elsewhere in our app...
var chicagoStore = Object.create(ChicagoPizzaStore);
var pizza = chicagoStore.createPizza('veggie');
console.log(pizza.description); // returns 'Veggie, Deep-dish Chicago Pizza'
```


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