상속

의사 클래스 방식

> var Mammal = function (name) {
    this.name = name;
    this.says = function () {
        return this.saying || '';
    }
};
> var Cat = function (name) {
    this.name = name;
    this.saying = 'meow';
};
> Cat.prototype = new Mammal();

> var myCat = new Cat('nabi');
> myCat.name;
'nabi'
> myCat.says();
'meow';

> Function.prototype.inherits = function (Parent) {
    this.prototype = new Parent();
    return this;
};
> var Cat = function (name) {
    this.name = name;
    this.saying = 'meow';
}.inherits(Mammal);

프로토타입 방식

> var myMammal = {
    name: 'mammal',
    says: function () {
        return this.saying || '';
    }
};
> var Cat = function (name) {
    this.name = name;
    this.saying = 'meow';
};
> Cat.prototype = myMammal;
> var myCat = new Cat('nabi');
> myCat.says();
'meow'

> Object.create = function (parent) {
    var F = function () {};
    F.prototype = parent;
    return new F();
};
> myCat = Object.create(myMammal);
> myCat.name = 'nabi';
> myCat.saying = 'meow';
> myCat.says();
'meow'

함수를 사용한 방식

> var mammal = function (spec) {
    var that = {};
    that.says = function () {
        return spec.saying || '';
    };
    return that;
};
> var cat = function (spec) {
    spec.saying = spec.saying || 'meow';
    var that = mammal(spec);
    return that;
};
> var myCat = cat({name: 'nabi'});
> myCat.says();
'meow'