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A lesson learned in including javascript libraries properly

·453 words·3 mins
Lucas Melin
Lucas Melin
Focused on helping developers succeed.

I figured I’d sit down and quickly add a navigation header to my site just to have it in place, so that I could add links to it later.

After reading over the Bootstrap documentation, I thought it seemed rather straight-forward, so I quickly whipped up a few lines of Jade into a serviceable navigation header with a few link elements in it — one to the homepage and one to the blog portion.

(As a quick side note, I’m really enjoying using Jade, if only for the fact that it helps avoid the pesky problem of forgetting closing div and span tags.)

Satisfied with the look of the navigation header, I resized my browser and the navigation did indeed collapse just like the documentation advertised, and I was pretty pleased with how simple it had all been.

“Just a matter of including the Bootstrap javascript libraries and any dependencies and we’ll be all set.” I thought to myself. So I downloaded the compiled javascript files provided by bootcamp and added them to a folder in my harp server directory, and appended these two lines near the top of my layout.jade document at the root of my server.

script((src = "/js/bootstrap.min.js"));
script((src = "//"));

“Simple,” I thought “the precompiled Bootstrap css is right on my server and the jquery is just served by Google’s CDN.”

But when I ran the harp server command from the terminal, the supposedly now collapseable navigation — the navigation still didn’t collapse. So of course my first thought was that I referencing an incorrect id in my layout.jade file, or that I was somehow calling a javascript plugin with the wrong name.

I carefully reread the documentation, checking each id and plugin name. It seemed okay to me. Next, I searched for a separate source of documentation. I found a few articles and even a youtube video, but it really seemed like I had added the lines properly for the navigation header to work.

Finally, I figured I’d just comment out all my navigation code and shoehorn in Bootstrap’s pure HTML into my layout.jade. Aha! It didn’t work either, so I double-checked the two lines of code I had added earlier to include the necessary javascript libraries. I could see that my server was serving them correctly, because they were properly included in the page source. But, crucially, I had messed up the order in which I had added the two files. I quickly switched the order:

script((src = "//"));
script((src = "/js/bootstrap.min.js"));

And suddenly everything was up and running as it should.

Lesson learned: Include javascript dependencies before the plugin file itself.

And also maybe don’t work on code when I’m sorely in need of some sleep.