save-load.js

var HpPotion = function(settings){
    settings = settings || {};
    _.extend(this, settings);

};

HpPotion.prototype = {
    constructor: HpPotion,
    slug: 'hp_potion',
    quantity: 1,
    // doesn't actually need a load function in this example
    load: function(saveData){

    },
    getSaveData: function(){
        return {
            isSaveData: true,
            slug: this.slug,
            quantity: this.quantity
        };
    }
};

var ItemsBySlug = {
    hp_potion: HpPotion
};

var Player = function(settings){
    settings = settings || {};
    _.extend(this, settings);

    this.items = [];
    this.sprite = spriteCreator.createSprite(this.race);

    if(settings.isSaveData){
        this.load(settings);
    }
};

Player.prototype = {
    constructor: Player,
    sprite: null,
    race: 'human',
    items: null,
    addItem: function(item){
        this.items.push(item);
    },
    load: function(saveData){
        var items = saveData.items;
        for (var i = 0; i < items.length; i++) {
            var itemData = items[i],
                ItemConstructor = ItemsBySlug[itemData.slug],
                item = new ItemConstructor(itemData);
            this.addItem(item);
        }
    },
    getSaveData: function(){
        var items = [];
        for (var i = 0; i < this.items.length; i++) {
            items.push(this.items[i].getSaveData());
        }
        return {
            isSaveData: true,
            race: this.race,
            items: items
        };
    }
};


var player = new Player();
var playerSaveData = player.getSaveData();
var loadedPlayer = new Player(playerSaveData);