Copy From https://speakerdeck.com/addyosmani/scaling-your-javascript-applications

basketModule.js

var basketModule = (function() {
    var basket = [];
    
    return {
        addItem: function(values) {
            basket.push(values);
        },
        getItemCount: function() {
           return basket.length;
        },
        getTotal: function() {
            var q = this.getItemCount(),p = 0;
            while(q--) {
                p += basket[q].price;
            }
            return p;
        }
    };
})();

var item = {"price": 30};
var item2 = {"price": 20};

basketModule.addItem(item);
console.log(basketModule.getItemCount());
basketModule.addItem(item2);
document.getElementById("result").innerHTML = basketModule.getTotal();

//

facade.js

var moudle = (function() {

    var _private = {
        i: 5,
        get: function() {
            console.log("Get Value: " + this.i);
        },
        set: function(val) {
            this.i = val;
        }
    }
    
    return {
        facade: function(args) {
            _private.set(args.val);
            _private.get();
        }
    }

});

resuable.class.js

function Tasker($, options) {

    var internal = [];
    
    var value1 = options.value1;

    function pushItem(item) {
        internal.push(item);
    }
    
    function getLength() {
        return internal.length;
    }
    
    function appendText() {
        $("div").append("Some appended text.");
    }
    
    function getOptionsValue(key) {
        return options[key];
    }
    
    return {
        pushItem: pushItem,
        getLength: getLength,
        appendText: appendText,
        getOptionsValue: getOptionsValue
    };

}

var t1 = Tasker(jQuery, { value1: "t1"});
var t2 = Tasker(jQuery, { value1: "t2"});

t1.pushItem(1);
console.log("t1 len " + t1.getLength());
console.log("t2 len " + t2.getLength());

t2.pushItem(1);
console.log("t1 len " + t1.getLength());
console.log("t2 len " + t2.getLength());

t1.pushItem(1);
console.log("t1 len " + t1.getLength());
console.log("t2 len " + t2.getLength());

t1.appendText();

console.log("t1 key " + t1.getOptionsValue("value1"));
console.log("t2 key " + t2.getOptionsValue("value2"));