Module, Singleton and Observer Patterns

// Module Pattern
var Module = function() {
    _private1 = "private";
    _history = [];
 
    function _privateReturner() {
        return _private1;
    }
 
    function _privateSender(set) {
        _history.push("From "+_private1+" to "+set);
        _private1 = set;
    }
 
    function _getHistory() {
        return _history;
    }
 
    return {
        publicReturner: _privateReturner,
        publicSender: _privateSender,
        publicHistory: _getHistory
    }
};
/*
var mod = new Module();
console.log(mod._private1); // undefined
console.log(mod.publicReturner()); // private
mod.publicSender("fishly");
mod.publicSender("fishly2");
mod.publicSender("bob");
mod.publicSender("kevin");
console.log(mod.publicReturner()); // fishly
console.log(mod.publicHistory());
*/
 
// Singleton Pattern
var Singleton = (function() {
    var _private1 = 1;
    var _private2 = 2;
    var _total = 0;
 
    function _privateFunc() {
        _total = _private1 + _private2;
    }
 
    function getter() {
        return _total;
    }
 
    function setterReset(newVar) {
        _total = newVar;
    }
 
    return {
        getter: getter,
        setterReset: setterReset,
        publicVar: 1,
        changePrivate: function() {
            _privateFunc();
        }
    }
})();
/*
Singleton.setterReset(0);
console.log(Singleton.getter());
Singleton.changePrivate();
console.log(Singleton.getter());
*/
 
// Observer pattern
function Observer() {
    this.fns = [];
}
 
Observer.prototype = {
    subscribe: function(fn) {
        this.fns.push(fn);
    },
 
    unsubscribe: function(fn) {
        this.fns = this.fns.filter(
            function(el) {
                if ( el !== fn ) {
                    return el;
                }
            }
        );
    },
 
    fire: function(o, thisObj) {
        var scope = thisObj || window;
        this.fns.forEach(
            function(el) {
                el.call(scope, o);
            }
        );
    }
};
/*
var o = new Observer;
o.fire('here is my data');
 
var fn = function fn() {
    console.log('data data');
};
var fn3 = function fn3() {
    console.log('data data3 ');
};
o.subscribe(fn);
o.subscribe(fn3);
o.unsubscribe(fn);
o.fire('here is my data');
*/