Lazy Load External Javascript Files

Question

I am trying to write a javascript class that loads script files as they are needed. I have most of this working. It is possible to use the library with the following Syntax:

var scriptResource = new ScriptResource('location/of/my/script.js');
scriptResource.call('methodName', arg1, arg2);

I would like to add some additional syntactic sugar so you could write

var scriptResource = new ScriptResource('location/of/my/script.js');
scriptResource.methodName(arg1, arg2);

I'm almost certain that this isnt possible but there may be an inventive solution. I guess what there need to be is some sort of methodCall event. SO the following could work

ScriptResource = function(scriptLocation)
{
    this.onMethodCall = function(methodName)
    {
        this.call(arguments);
    }
}

This code is obviously very incomplete but I hope it gives an idea of what I am trying to do

Is something like this even remotely possible?

Answer 1

If the set of method names is limited, then you could generate those methods:

var methods = ["foo", "bar", "baz"];
for (var i=0; i<methods.length; i++) {
    var method_name = methods[i];
    WildCardMethodHandler[method_name] = function () {
        this.handleAllMethods(method_name);
    };
}

edit: Posted this answer before the question changed dramatically.

Answer 2

There is a non standard method, __noSuchMethod__ in firefox that does what you're looking for
have a look at
https://developer.mozilla.org/en/Core_JavaScript_1.5_Reference/Global_Objects/Object/noSuchMethod

so you could define

obj.__noSuchMethod__ = funtion( id, args ) {
    this[id].apply( this, args );
}

Answer 3

An intermediary solution might be to have syntax such as:

var extObj = ScriptResource('location/of/my/script.js');  
extObj('methodname')(arg1,arg2);

the code might look like this:

function ScriptResource(file) {
  return function(method) {
    loadExternalScript(file);
    return window[method];
  }
}

All kinds of assumptions in the code above, which I'd let you figure out yourself. The most interesting, IMHO, is - in your original implementation - how do you get the proxyied method to run synchronously and return a value? AFAIK you can only load external scripts asynchronously and handle them with an "onload" callback.