Using cargo cult code is like wearing cargo pants. People might make fun of you for wearing them, but they’re quite practical.

When I first tried to add comments to this blog, it seemed that I had picked the wrong cult to join. Granted, I might not have been very good at debugging javascript at that time. But with great frustration, I pushed commit after commit and did not see anything appear. I will try to go into an autopsy of that code, but first…

What Did Work

I stole Leigh Johnson’s code from here, which was originally stolen from yet another source. At least I can kind of explain this code now.

(function() {
    var d = document.createElement('script');
    d.type = 'text/javascript';
    d.async = true;
    d.src = '//alancoding.disqus.com/embed.js';
    (document.getElementsByTagName('head')[0] || document.getElementsByTagName('body')[0]).appendChild(d);
})();

NOTE: please tell me everything I have horribly wrong here in comments, because I probably am wrong.

Going from the outer layer first, this is a function definition. However, the syntax with the brackets at the end executes it. So this

Within this function, you start off with the document. Then you create a script element, which establishes its own scope. Inside of this namespace, a few more variables are attached, particularly type, async, and src.

Next, inside of the OR condition within brackets, I think that we are attempting to grab the document head. If that doesn’t work (resolves to false as well), then we try to grab the document body. Presumably either will work, but this is trying to get compatibility with different DOM structures.

After we have that element, the script element is appended to it.

Beyond that, it’s hard to say what happens. It executes the Disqus code. I’m guessing that it injects HTML (and other stuff) into whatever place the bounding <script> tags defined. It probably does a lot of relatively sophisticated stuff.

What I Got Wrong

Using the function disqus_config() constituted a fairly major red herring. Really, that was defined in the imported script from Disqus proper. But then things got complicated. What version of this method was really working in what context?

The door was left open for multiple different kinds of errors. Could it have been that d.head just didn’t work and threw some blocking errors? Maybe the Date() method did. Even assuming no errors were produced inside of the function, things didn’t get connected correctly somehow.

Other JS / Angular stuff

Today I was trying to dust off the CodeCademy course on AngularJS. There was one thing that frustrated to extensively. I couldn’t copy the files and test them by just running my browser. It turned out that I was just missing the invocation of the app.js code which defined the module, as well as the controller. These needed to be called directly in the index.html, which is obviously the page that a visitor lands on.

So I understood the concepts, but not the logic behind linking them all.

I guess that’s kind of part of the problem with online learning in the first place. Giving students rails to drive on keeps them from going off the rails and learning more on their own. In this case, giving a very well-designed directory structure wasn’t bad per-se. For me, the problem was the directory structure was combined with a host of other irrelevant distractions in the code. If you don’t start off with just what’s important, you never know what’s necessary to do a new project.