Is there a way to dynamic load a library in suitescript or does everything need to be done at the define? I want to do something like:

function someFunction(pathToLibrary) {
  ......load Library
  ......call function in library
}

We use this function:

function loadModule(modPath) {
    var dyn;
    require([modPath], function(d) {
        dyn = d;
    });

    return dyn;
}

It will return an object for the module.

This looks a little dangerous to me because

loadModule()

could return before the require is completed?

In server scripts, the require runs synchronously so it won't return before the module is loaded. I haven't tested it client side but I suspect it wouldn't work due to what you mentioned.

yeah I am only using it server side