TL;DR: startSpan is easier and measures a duration. Use it if your work won’t create any subspans. startActiveSpan requires that you pass a callback for the work in the span, and then any spans created during that work will be children of this active span. I’m instrumenting a Node.js app with OpenTelemetry, and adding some …
Today, I found a bug before I noticed it. Like, it was subtle, and so I wasn’t quite sure I saw it–maybe I hadn’t hit refresh yet? Later, I looked at the trace of my function and boom, there was a clear bug. Here’s the function with the bug. It responds to a request to …
Sometimes the obvious, default API is never what you want. That’s when you have to memorize the “do things right” flag. For yargs, the command-line argument parser for Node.js, specify options and subcommands like this: There. Next time I can cut and paste this instead of scouring the internet for how to make yargs do …
import * as fs from “fs”; import { promisify } from “util”; const content: Promise<string> = promisify(fs.readFile)(“path/to/the/file”, { encoding: “UTF-8” }) I am tired of looking that up over and over every time I want to read a file into a promise in Node using TypeScript, so here it is. Next time, bring me here, Google. The promisify call turns fs.readFile from a callback-based method to a promise-based one. promisify accepts …
Karl Popper defines rationality as: basing beliefs on logical arguments and evidence. Irrationality is everything else. He also defines comprehensive rationality as: only logical arguments and evidence are valid basis for belief. But this belief itself can only be accepted by choice or faith, so comprehensive rationality is self-contradictory. It also excludes a lot of …
A few hundred years ago, we decided that circular causality was a logical fallacy. All causes are linear. If something moves, then something else pushed it. If you want to see why, you have to look smaller; all forces derive from microscopic forces. Yet as a human, I see circular causality everywhere. autocatalytic loops in …
It’s all that THAT Conference is not THOSE conferences. It’s about the developer as more than a single unit: this year, in multiple ways. I talked about our team as a system — more than a system, a symmathesy. Cory House said that if you want to change your life, change your systems. As humans, our greatest power …
Lately I’ve been wrestling with npm. Here are some rules I’ve learned: Use `npm ci` rather than `npm install` `npm ci` will bring down exactly the dependencies specified in package-lock.json. `npm install` does more than that; it also tries to update some libraries to a more recent version. Sometimes it updates URLs or nonsense in …
TL;DR: creating a Promise splits off another path of execution, and the Promise object represents the end of that path. Calling .then adds code to the end of that path. You can think of your program’s execution as following a piece of yarn. this video illustrates the difference between a synchronous program and the same program …
Read moreUnderstanding Promises in JavaScript (with yarn and Legos)
TL;DR: when using an object as a dictionary in TypeScript/ES6, iterate through it using `Object.keys()`. Coming from statically typed languages, I keep looking for a Map or Dict type in TypeScript (or JavaScript). People use objects for this, though. Objects have key-value pairs in them, and you can add them and delete them and declare …