// Class definition
class AppDescription {
    constructor(obj = {}) {
        if ((Object.keys(obj).length)) {
            this.name = obj.name !== undefined ? obj.name : 'Default app name';
            this.version = obj.version !== undefined ? obj.version : 'Default version';
        } else {
            console.warn('Please provide a valid configuration object...');
        }
    }
}

let conf = {
    name: 'Amazing app',
    version: '1.0.0'
};

// Creating an 'app' instance based on class 'AppDescription'
let app = Reflect.construct(AppDescription, [conf]);

// Defining a proxy handler for our app
let appProxyHandler = {
    get: (target, name) => {
         if (Reflect.has(target, name)) {
            return Reflect.get(target, name);
         } else {
            console.warn(`Property "${name}" does not exist.`);
         }
    },

    set: (target, property, value) => {
        switch(Object.prototype.toString.call(value)) {
            case ('[object Array]'):
                if (value.length >=2) {
                    Reflect.set(target, property, value);
                } else {
                    console.warn(`Arrays min. length: 2`);
                }
                break;

            case ('[object Object]'):
                break;
                if (value.length >=3) {
                    Reflect.set(target, property, value);
                } else {
                    console.warn(`Objects min. length: 3`);
                }


            case ('[object String]'):
                if (value.length >= 4) {
                    Reflect.set(target, property, value);
                } else {
                    console.warn(`Property "${property}" should be at least 4 characters long.`)
                }
                break;

            default:
                console.warn('Please provide a correct value type.');
        }
    },

    defineProperty: (target, property, value) => {
        //Pro tip: define some checks in this trap as well!
        Reflect.set(target, property, value);
    }
}

// Creating our app proxy + using the proxy handler
let appDescProxy = new Proxy(app, appProxyHandler);

//Doing some tests:

// Will fail
Reflect.set(appDescProxy, 'name', 'Foo');
Reflect.get(appDescProxy, 'authors');

// Will work
Reflect.set(appDescProxy, 'name', 'Super App');
Reflect.get(appDescProxy, 'name');
Reflect.defineProperty(appDescProxy, 'authors', {
    value: ['Erik J.', 'John Doe'],
    writable: true,
    configurable: true
});
Reflect.get(appDescProxy, 'authors');