Category: Deno

how deno might have gotten its name

whbeebe

Deno ( https://deno.com/ ) is a runtime for JavaScript, TypeScript, and WebAssembly that is based on the V8 JavaScript engine and written in Rust ( https://www.rust-lang.org/ ). Deno was co-created by Ryan Dahl, who also created Node.js.

I have moved away from Node to Deno in part because I can clone the entire Deno source tree and play around in it, and in part because over time I’ve grown tired of Node and its various peculiarities. I can do this because I’m retired, but if I ever decided to venture out back into the world I sincerely doubt that my Deno skills would be consider an asset; the world seems to run overwhelmingly on Node.

While I was tinkering with Deno I kept wondering where its name came from. As I sat staring at the screen, I noticed that Deno has the same four letters as Node, and that Deno is spelled in alphabetical order. That’s when I suddenly tried this:

Both Node and Deno will evaluate the same JavaScript function on the command line, which is: split the string ‘node’ into a list of individual ASCII characters, sort the list, then join the sorted list back into a string. I have no idea if this is what Ryan Dahl did, but it seems a simple enough thing to do.

be careful of library versions and old code with deno

whbeebe

I have always been impressed with Deno ( https://deno.land ). It was designed and implemented as a secure server-side JavaScript and Typescript runtime by the same developer who create Node.js, Ryan Dahl ( https://en.wikipedia.org/wiki/Ryan_Dahl ). I’ve always been impressed by Deno because Deno is written in Rust.

Unfortunately that doesn’t mean I’ve been using Deno. After my initial infatuation with Deno I left my work with Deno to rest idle. I had lots of grand ideas, but right now I’ve not got much to show for it except a bunch of small to medium sized incomplete (and I’m being charitable by calling them incomplete) projects. Because I’m building a head of steam around Micro Python and Circuit Python embedded work, I thought I’d create a local HTTPS server to handle all of them. A tiny cloud, if you will.

So I dusted off one of the promising incomplete projects and began to work with it again. That’s when I ran into errors all over the place with code that did work when I stopped. As usual I whittled one of the problems down to a few lines of example code that would produce one of the errors. Here’s what it looks like.

import { serve } from "https://deno.land/std/http/server.ts";const server = serve({ port : 8000 });for await (const server_request of server) {server_request.respond({ body: "Deno server instance created\n" });}

Running it produces the following:

opos@fedora:~/Develop/DenoWork$ deno run --allow-net my-server-bad.js Listening on http://localhost:8000/error: Uncaught TypeError: server is not async iterablefor await (const server_request of server) {   ^at file:///home/popos/Develop/DenoWork/my-server-bad.js:3:36

So code that once worked no longer does. Line 3 in the source is the culprit. So I go googling and rapidly find the solution on Stack Overflow ( https://stackoverflow.com/questions/70963882/deno-serve-imported-from-std-http-server-ts-is-not-async-iterable ). Sure enough, when I follow the advice in that post and make one change, it works like it did when I put it aside.

import { serve } from "https://deno.land/std@0.106.0/http/server.ts";const server = serve({ port : 8000 });for await (const server_request of server) {server_request.respond({ body: "Deno server instance created\n" });}

The correction was to add the “@0.106.0” version to the import statement in line 1. Just lovely. So, do I go through my code and start locking down versions on everything? Or do I do the right thing and learn the new way of doing things? I’m retired and things like this are my hobby, not a paying job. There’s a part of me that wants to be lazy and just lock everything down and live with that. But there’s the other part that is yelling about being a lazy bum and a hypocrite for wanting the easy way out. I think what I’ll do is sit back for a bit and rethink how I want all of this to be. Maybe if I learn the New Ways, then I should rewrite from the ground up. And this time don’t let it go for over a year.