lib/utils.js
function (f, proto) {
        function Ctor() {}
        Ctor.prototype = proto
        f.prototype = new Ctor()
        f.prototype.constructor = Ctor
        return f
    }
function (f, proto) {
        function Ctor() {}
        Ctor.prototype = proto
        f.prototype = new Ctor()
        f.prototype.constructor = Ctor
        return f
    }
function ( f , proto ) { function Ctor ( ) { } Ctor . prototype = proto f . prototype = new Ctor ( ) f . prototype . constructor = Ctor return f }
Create a class with specified proto
Create a class with specified proto