I think the best approach, if I understand your problem correctly, would be to define each of your instantiation/configuration blocks as a separate “module” in YUI Loader.

http://developer.yahoo.com/yui/examples/yuiloader/yl-addmodule.html

Call the insert() method on the modules in the order you want them to fire (ie, in the order you want your components to instantiate). Let YUI Loader do the heavy lifting for you — it will calculate dependency trees for you and load whatever is missing (and do it with combo-handled requests) as needed, and only when needed.

This may mean a few additional requests, but the modularity it gives you is worth it in many cases.

If I’ve missed the boat on your question here, let’s take the conversation over to YDN-JavaScript.

Regards,
Eric

Great overview, thanks; I just have a question about best practices (and scoping) when loading multiple components.

Let’s say I have something like require: [X, Y,Z], where X, Y and Z are arbitrary YUI components.

Let’s also say that I have non-trivial instantiation logic for each of these components.

My question is how best would/could I structure my onSuccess() method to keep the all the instantiation logic from clashing?

I’d like to generate the loader config script on the server, perhaps with $module=>$setUp pairs, and my thought is that I need to use function literals themselves wrapped in parentheses to get what I’m after. (My trouble is that it’s precisely here that, for me at least, JavaScript gets confusing… ;-))

Thanks again,
Carlton

Here are a couple of followups: 1. You’re absolutely right — Loader brings in all the required files that it perceives are needed for a given implementation. So when we ask for TabView, it looks at what’s on the page and gives us anything else we need to use TabView. 2. Why would you use method 1 instead of method 2? Well, if you really wanted the lightest seed file, 1 is the best option. In the case where you’re not going to be using any scripts in the initial paint of the page and everything is going to be layered on unobtrusively, this is the lightest starting point. But (3.), it’s often the case that you *do* need to do thing like attach event listeners in the course of building a page, so and method 2 is good for that, and it’s a good, performant compromise. 4. As for the final method, you’re right — I didn’t convey that very well. The goal is to have a page that works well without JavaScript, and putting the whole JavaScript payload at the top of the page generally needs to be done only when the page *requires* JavaScript to function correctly. If you take this single-file approach, though, putting the file at the bottom of the page *is* a good idea — that means that the page painted and functioned without the script, and the JavaScript was just there to add enhanced functionality.

Sorry for the confusion — please let me know if you have further questions.

-Eric

Next, when we get to method two I think we learn that one would never want to use method one. Perhaps method one should be described as “just so you see the big picture”. As it is, I find myself wondering when or why I would use #1, ie, what advantages it offers (since it is hard to imagine using YUI without DOM and Event).

The description of method 3 completely lost me. The motivation is “when on-demand won’t work” so my first thought is that I do not know what on-demand means, because on-demand means “use it and it will be there”. Then the example given for when it won’t work is just vague “script-driven” “core interactions” we want to render “as quickly as possible”…I find myself as a noob wondering what all that means, and an actual example of a page that won’t work and why would eliminate a lot of confusion.

Finally the method three commentary says “this file should appear as late as possible” and ends up explaining that that is why we should use method one or two. Hunh? Method three is why we should use method one or two? Then why am I being told about method three? Guessing: use method three if one’s page does not require the core during construction of the page, which won’t be often if one is having any fun at all with YUI.

Overall I sense there is a lot of good stuff in this article, but I find myself working hard to figure out what that good stuff is.