JavaScript and Unexpected Dependencies

I have recently been helping a few people debug issues they have with Microsoft Edge.

It’s quite common that I get sent code snippets of things that don’t work and it’s then up to me to put together a Workable project that displays the bug so that I can try and fix it.

It’s quite common that I get sent a code snippet with a dependency that the developer has forgotten to mention (or perhaps assumed I will know about). I get this one quite a bit:


    _.defaults(options, {blah: 'foo'});

The first time I saw it I got a “SCRIPT5009: ‘_’ is undefined” error in my console and I suspected the developer hadn’t sent me all of his code. You see, I’m not an Underscore.js user and so it took me about 10 minutes of searching before I realised that this code had a dependency on Underscore . I’ve heard about underscore. I’ve seen underscore before… But I just didn’t recognise it. I added Underscore.js to the project, My code now runs and I feel a little bit stupid.

Assumptions… Can be really annoying.

Published by thebeebs

Martin works for Microsoft as a Software Developer. He’s been a developer since the late 90s and loves figuring out problems and experimenting with code.