Protected protocol

Client.js

var d = new Person('David');
console.log('d.name:', d.name);
setTimeout(function(){
    console.log('d age', d.getAge());
}, 500);
console.log('d instanceof Person', d instanceof Person);
console.log('d instanceof ComputerSavvyPerson', d instanceof ComputerSavvyPerson);

var db = new ComputerSavvyPerson('David Bruant', 'JavaScript');
console.log('db.name:', db.name);
console.log('db.favoriteLanguage:', db.favoriteLanguage);
console.log('first letter secret', db.getSecretFirstLetter());
setTimeout(function(){
    console.log('db age', db.getAge());
}, 500);
console.log('db instanceof Person', db instanceof Person);
console.log('db instanceof ComputerSavvyPerson', db instanceof ComputerSavvyPerson);

var eve = new EvilPerson();
eve.attemptStealSecret(d);
eve.attemptStealSecret(db);

var eve2 = new EvilCompSavvyPerson();
eve2.attemptStealSecret(d);
eve2.attemptStealSecret(db);

ComputerSavvyPerson.js

// COMPUTER SAVVY PERSON
var ComputerSavvyPerson = makeSubclass(Person, function(Protected, Super){

    function ComputerSavvyPerson(name, favoriteLanguage){
        console.log('this in ComputerSavvyPerson', this);
        Super.call(this, name);
        this.favoriteLanguage = favoriteLanguage;
    }

    ComputerSavvyPerson.prototype = Super.protoChain({
        getSecretFirstLetter : function(){
            return Protected(this).secret[0];
        }
    });
    
    //console.log('ComputerSavvyPerson.prototype', ComputerSavvyPerson.prototype)

    return ComputerSavvyPerson;
    
});

Evil.js

function evilPersonDecl(Protected, Super){

    function EvilPerson(){
        this.attemptStealSecret = function(otherPerson){
            //console.log('Evil Person', 'Protected(otherPerson).secret read')
            var s = Protected(otherPerson).secret;
            console.log("Ahah! I tried to steal %s's secret! Here is what I got:%s", otherPerson.name, String(s));
        }
    }

    return EvilPerson;
}



var EvilPerson = makeSubclass(Person, evilPersonDecl);
var EvilCompSavvyPerson = makeSubclass(ComputerSavvyPerson, evilPersonDecl);

Person.js

// PERSON
var Person = makeConstructorWithProtected(function(Protected){

    function Person(name){
        Protected(this).secret = String(Math.random()).substr(2);
        console.info("person's secret", Protected(this).secret, "...shhhhhhh!!!...");
        
        Protected(this).age = 0;
        setInterval(function(){
            Protected(this).age++;
        }.bind(this), 100);

        this.name = name;
        console.log('this in Person', this);
    }
    
    Person.prototype = {
        getAge: function(){
            return Protected(this).age;
        }
    };
    
    return Person;
    
});

ProtectedProtocol.js

function makeProtectedStore(){
    var ownStore = new WeakMap();
    var childStoreGets = [];
    
    var ret = function(o){
        var protectedStore;
    
        // own store first
        protectedStore = ownStore.get(o);
    
        if(protectedStore)
            return protectedStore;
    
        // check in otherStores
        childStoreGets.some(function(storeGet, i){
            //console.log('traversing childStores', childStores.length, i);
            var s = storeGet(o);
            if(s === Object(s)){
                protectedStore = s;
                return true;
            }
            
            return false;
        });
        
        if(protectedStore){
            return protectedStore;
        }
        else{
            var s = {}; // create new store
            ownStore.set(o, s);
            return s;
        }
    };
    
    ret.addChildStoreGet = childStoreGets.push.bind(childStoreGets);
    ret.storeGet = ownStore.get.bind(ownStore);
    
    return Object.freeze(ret);
}


(function(global){

    var constructorToProtectedStore = new WeakMap();

    global.makeConstructorWithProtected = function(declaration){
        var protectedStore = makeProtectedStore();
        var constructorWithProtected = declaration(protectedStore);

        constructorToProtectedStore.set(constructorWithProtected, protectedStore);
        
        return constructorWithProtected;
    }

    global.makeSubclass = function(parent, declaration){
        var protectedStore = makeProtectedStore();
        var parentProtectedStore = constructorToProtectedStore.get(parent);
        parentProtectedStore.addChildStoreGet(protectedStore.storeGet);
        
        var constructorWithProtected = declaration(protectedStore, Object.freeze({
            call: function(obj){
                var args = Array.prototype.slice.call(arguments, 1);
                
                protectedStore(obj); // so that there is already an own protected store for the subclass instance
                return parent.apply(obj, args);
            },
            protoChain : function(obj){
                var proto = Object.create(parent.prototype);
                
                Object.getOwnPropertyNames(obj).forEach(function(n){
                    Object.defineProperty(proto, n, Object.getOwnPropertyDescriptor(obj, n));
                });
                
                return proto;
            },
            prototype: parent.prototype
        }));
        
        constructorToProtectedStore.set(constructorWithProtected, protectedStore);
        
        return constructorWithProtected;
    }

})(this);