Prototypes in Javascript

function Cat(name, color) {
this.name = name;
this.color = color;
}
Cat.prototype.age = 3;

var fluffy = new Cat("Fluffy", "White");
var scratchy = new Cat("Scratchy", "Black");

What is the value for fluffy.age and scratch.age?

Given that a function’s prototype is just an object, then what would happen if we started changing the properties of a function’s prototype after we created objects from it?

function Cat(name, color) {
this.name = name;
this.color = color;
}
Cat.prototype.age = 3;

var fluffy = new Cat("Fluffy", "White");
var scratchy = new Cat("Scratchy", "Black");
Cat.prototype.age = 4;

What is the value for fluffy.age and scratchy.age?

function Cat(name, color) {
this.name = name;
this.color = color;
}
Cat.prototype.age = 3;

var fluffy = new Cat("Fluffy", "White");
var scratchy = new Cat("Scratchy", "Black");
Cat.prototype = {age: 4};

What is fluffy.age and scratchy.age?

function Cat(name, color) {
this.name = name;
this.color = color;
}
Cat.prototype.age = 3;

var fluffy = new Cat("Fluffy", "White");
var scratchy = new Cat("Scratchy", "Black");

Cat.prototype = {age: 4};

var muffin = new Cat("Muffin", "Brown");

What is muffin.age?

function Cat(name, color) {
this.name = name;
this.color = color;
}
Cat.prototype.age = 3;

var fluffy = new Cat("Fluffy", "White");
var scratchy = new Cat("Scratchy", "Black");

fluffy.age = 4;

What is fluffy.age and scratchy.age?

function Cat(name, color) {
this.name = name;
this.color = color;
}
Cat.prototype.age = 3;

var fluffy = new Cat("Fluffy", "White");
var scratchy = new Cat("Scratchy", "Black");

fluffy.__proto__.age = 4;

What is fluffy.age and scratchy.age?