Coming back to JavaScript and TypeScript after a few years neck deep in Python and Hack, I kept hitting a number of new, cryptic errors when running NodeJS code in my dev environment: These errors are all related to importing, typechecking,…
For the last year and a half, I have been working at Instagram in Japan. It’s a bit of an unusual setup: I live and work remotely from Nara, Japan, in a timezone that few other Meta engineers work in (most of Instagram and Meta are spread a…
You often hear that “timing matters”. It helps to think about this as two related concepts: time and timing. For some things, time is more important than timing: For other things, timing is more important than time: What’s the difference be…
I just finished Oliver Sacks’ excellent Everything in Its Place. In it, he mentioned as an aside that the Ginkgo biloba tree is hundreds of millions of years old, and its phenotype has been practically frozen since then – a living fossil. O…
It’s 2021, and data management on the web still sucks. This is crazy! If you’re building a web app at scale you have plenty of options for data fetching, transport, caching, and management: Each of these does a few things well, leaving the
I don’t usually write about politics, but today was a weird day. Thousands of people gathered outside the Capitol building in Washington DC today, some of them going into the building, some with guns. A woman got shot. All of this in respon…
When typing React component props using TypeScript, I often see code that makes use of optional and nullable fields: In this example, Button is a React component that takes a prop text, and either an href or onClick prop controlling what ha…
If you have a tree with a node that has a property P, and all of its parents also need to have property P, then P is contagious. As a programmer, that seems bad. Bubbling up breaks encapsulation and makes things harder to compose. If I have…
I spent the last year and a half writing my first technical book for O’Reilly (Programming TypeScript). I’d never written a technical book before. In fact, prior to the 300-page book, the longest thing I’d written was a 20-something-page pa…
Derived state for frontend applications comes up a lot. State B depends on State A, so after you update A, by the time you read B you want it to be updated based on the latest value of A. There’s a bunch of ways to model this, involving dif…
2017 has been a wild year for JavaScript and frontend development. A new version of the language was released, GraphQL was announced, compile-to-JavaScript languages were rolled out by the dozen, React became the default frontend framework,…
Let’s get right into it. From Redux’s official TodoMVC example, here’s how to take a Todo app and add an Add Todo action: Yup, you’ve probably seen this before. It’s the Redux way: dispatch an Action in your React component (making sure tha…