var Medium = function(fn, args){
    var __fn = cloneFunction(fn);
    var __length = fn.length;
    var __args = args.length >= fn.length ? args : fill(fn.length, args);
    var __self = this;

    this.getFn = function(){ return cloneFunction(__fn) };
    ...
}

Medium.prototype.pass = function(sprdArgs){
    var fnArgs = this.getArgs();
    return arguments.length > 0
         ? this.use("load", arguments)
         : this.use("update", fnArgs);
}
...

var Medium = function(fn, args){
    ...
    this.method = function(thisArg, funcName, args){
        var funcs = {
            load: function(args){ ... },
            update: function(params){ ... },
            execute: function(){ ... }
        };

        return thisArg === __self
            ? funcs[funcName].apply(thisArg, args)
            : null;
    }
}

Medium.prototype.use = function(funcName, sprdArgs){
    var args = clone(arguments);
    var sprdArgs = filter(args, function(elem, i){
        return i !== 0;
    });

    return this.method(this, funcName, sprdArgs);
}