Prototypal Inheritance

coffee.coffee

object = (o)->
  F = ->
  F.prototype = o
  new F()

# object to inherit from
parent = name: "Papa"

# the new object
child = object parent

# testing
console.log child.name # "Papa"


# parent constructor
Person = ->
  # an "own" property
  @name = "Adam"

# a property added to the prototype
Person::getName = ->
  @name

# create a new person
papa = new Person()
# inherit
kid = object papa
# test that both the own property
# and the prototype property were inherited
console.log kid.getName() # "Adam"


# parent constructor
Person = ->
  # an "own" property
  @name = "Adam"
# a property added to the prototype
Person::getName = ->
  @name
# inherit
kid = object Person.prototype
console.log(typeof kid.getName) # "function", because it was in the prototype
console.log(typeof kid.name) # "undefined", because only the prototype was inherited


# Addition to ECMAScript 5
child = Object.create parent

child = Object.create parent, age: value: 2
console.log(child.hasOwnProperty("age")) # true

original.js

function object(o) {
	function F() {
	}

	F.prototype = o;
	return new F();
}

// object to inherit from
var parent = {
	name:"Papa"
};

// the new object
var child = object(parent);

// testing
console.log(child.name); // "Papa"


// parent constructor
function Person() {
	// an "own" property
	this.name = "Adam";
}
// a property added to the prototype
Person.prototype.getName = function () {
	return this.name;
};
// create a new person
var papa = new Person();
// inherit
var kid = object(papa);
// test that both the own property
// and the prototype property were inherited
console.log(kid.getName()); // "Adam"


// parent constructor
function Person() {
	// an "own" property
	this.name = "Adam";
}
// a property added to the prototype
Person.prototype.getName = function () {
	return this.name;
};
// inherit
var kid = object(Person.prototype);
console.log(typeof kid.getName); // "function", because it was in the prototype
console.log(typeof kid.name); // "undefined", because only the prototype was inherited


/* Addition to ECMAScript 5 */
var child = Object.create(parent);

var child = Object.create(parent, {
	age:{ value:2 } // ECMA5 descriptor
});
console.log(child.hasOwnProperty("age")); // true