Deno is a re-imagining of Node: still JavaScript for the server and command line, still based on V8, but with a drastically improved build story, simplified (hell, genuinely simple) dependencies, and a vastly improved standard library and web compatibility story. I’ve been using it on-and-off for hobby work for a couple of years now,[1] and I’ve really enjoyed playing with it.

One especially unique feature of Deno is its security model. By default, Deno scripts aren’t allowed any dangerous access: not the file system, not the network, not environment variables, not even high-resolution timers. Basically, they need to be hermetically sealed scripts, or be explicitly granted permissions by the user to do anything. The upshot is that you can blindly run a script (e.g. the official welcome script, via deno run safe in the knowledge you can’t hose your computer.

For awhile, I’d had an idea that I’d port some of my personal programs such that I could simply deno run them right off my GitHub account, rather than installing them. In practice, that proved a bit tricky: Deno’s APIs for reading local files (e.g. Deno.readFileSync) were different from reading remote files (via fetch), so handling a script running both locally and remotely, if it required external resources, ended up being a bit of a pain and require varying amounts of conditional branching. Not a deal-breaker in a strict sense, but it took enough fun away I didn’t bother.

But I was happy to discover that Deno 1.16 actually added file:// URL support to fetch. That means that fetch(new URL("./file.txt", import.meta.url)) will work both when run locally and when run remotely. I gave this a shot in the silliest way imaginable, and, well…feel free to enjoy my Deno port of fortune, Dortune. Sure, you can clone and run it locally, but you can also do deno run --allow-net and enjoy the exact same code working remotely without installing anything.

Granted, this particular example is fairly ridiculous, but I’m honestly quite excited about having a suite of personal utilities I can keep up-to-date transparently and that don’t care where they run.

  1. At least, when I’m not playing with Factor. ↩︎