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    Swizec's articles in the "technical" category

    I aim to write mindblowing emails with real insight into the career and skills of a modern software engineer. "Raw and honest from the heart!" as one reader described them.

    Below are 293 articles filed under technical. Enjoy ❀️

    Async React with NextJS 13

    We look at React's native async support and how to use it in a NextJS 13 app. Learn how to use async components, parallel loading states, and caching with React.js and NextJS 13.

    Reader question: useReducer or XState?

    Following up from my article about XState and Stately.ai, fellow reader S. asked if `useReducer` could ever be relevant when using state machines in React code. Yes! Here's how

    When your brain is breaking, try Stately.ai

    Two years ago I wrote about using XState after building a UI interaction so twisted my brain leaked out my ears. It helped. Now the creators have made something even better – Stately.ai 😍

    Over-engineering tweet embeds with web components for fun and privacy

    A way to embed tweets in static sites with full pre-renders and live updates using just 9kB of client-side JavaScript, 2 HTTP requests, and full reader privacy ✌️

    useCallback is a code smell

    One of my favorite ways to simplify and de-gotcha React code is to rip out all the useCallback and useMemo drama. 90% of the time you don't need it.

    Your code doesn't matter

    "Your code doesn't matter" is something experienced programmers say, between the lines, when they sound like complete lunatics. But what do they mean? Why does everyone say it?

    Promise.allSettled, a wonderful tool for resilient code

    The pros and cons of different approaches to writing resilient code that handles partial failures

    Saving time in UTC doesn't work and offsets aren't enough

    Lessons from a painful outage with timezones, UTC offsets, and database clients that took a whole week to resolve.

    A quick lesson in writing resilient code

    On the backend anything can and will fail. How do you deal with that?

    A new VSCode extension makes state machines shine on a team

    When you grok state machines, a new world of computational beauty and software design opens in front of your eyes. Things that used to be hard become easy. The impossible becomes possible. And you turn into that annoying team member.

    Small choices can wreck your codebase

    wanna see the strangest looping construct I've found in production code?

    How defensive coding leads to bloat

    Defensive coding is an important lesson and over time and engineers it leads to massive bloat, if you're not careful.

    How to configure Jest with TypeScript

    Using plain Jest on a TypeScript codebase is kinda rough. No types in tests no thanks. Making Jest and TypeScript work together smoothly is something you do just rarely enough to forget the details. Hope this helps you and future me too ✌️

    Anything's a sorting problem if you squint hard enough

    What's the most algorithmically fun code you've written recently? πŸ€” Here's mine: A dataviz using a grid of triangles that fits into the client's logo.

    You don't need a big team to automate your work

    The opposite of folks who follow every FAANG trend and over-engineer their companies to death, are the folks who *never* take advice from the big boys.

    React 18 and the future of async data

    Friend, I have glimpsed the future and it is amazing. React 18 is shipping with Suspense and startTransition for deferred component rendering, but not data loading. That's coming in a future 18.x version.

    A surprising feature of JavaScript optional chaining

    This blew my mind, thought you'd like it too. You can do more with ?. than you thought.

    Use Netlify's _redirects on Gatsby Cloud

    Something always goes wrong when you change hosting providers. πŸ˜… For me it was redirects. A vital feature of any site migration.

    A better React 18 startTransition demo

    Demoing startTransition is hard. Modern computers are too fast πŸ˜… – Dan Abramov, a React core team member, helped me fix it up. Here's what I learned

    Trying out React 18 Alpha

    I read everything about React 18 Alpha, trawled through the work group, and ran some experiments. Here's what you'll wanna know.

    A fun security bug with static rendering – CodeWithSwiz #31

    The flash of unlocked content is great fun for any paywall

    Build privacy-focused blazing fast tweet embeds – CodeWithSwiz 30

    Twitter embeds every tweet on your page as an iframe. Loads 1.2MB of JavaScript, makes 20+ HTTP requests and uses 100+ DOM nodes. πŸ’©

    Twitter embeds without JavaScript, pt1 – #CodeWithSwiz 29

    Continuing our quest for better Lighthouse scores, more reader privacy, and less JavaScript we attacked the next biggest culprit πŸ‘‰ Twitter.

    Your serverless questions, answered

    When talk comes to serverless, engineers have lots of questions. Here are some answers 😊

    Go full-stack in 5min with your first cloud function

    How *do* you build a JavaScript function that runs in the cloud serverlessly? Here's how to get started with Vercel, Netlify, or AWS Lambda

    Can you automate love?

    What's the laziest thing you've ever built? For me it's a bot that sends cute pictures every day

    If you can JavaScript, you can backend

    When you think of a backend or server developer, who comes to mind? A wizard of arcane magics. The future belongs to full-stack frontend engineers.

    How a $12 AWS bill powers a $50k business

    my point is that running server code on the web has become ridiculously cheap *and* easy

    Variants – a quick tip for better React components

    Reusable components like to grow boolean props for different situations and complexity soon blows up. Variant props are the perfect solution.

    Reverse engineer a GraphQL API to automate love notes – CodeWithSwiz 24

    We used a man-in-the-middle attack to snoop an app's API traffic, replayed it in a GraphQL client, and successfully put it inside an AWS Lambda 🀘

    A TypeScript trick for reusable hooks

    Reusable hooks are all fun and games until TypeScript starts yelling at you about incompatible types.

    The Magic Function principle

    Write functions, mostly magic.

    [CodeWithSwiz 21] useAuth beta support for Firebase πŸŽ‰

    It works! useAuth has beta-level support for Firebase Auth πŸ₯³ I did not expect that to take 3 sessions.

    Tech interview best practice that fails in life

    Tech interviews have a magic answer: The hashmap. And it's not always best on the job.

    [CodeWithSwiz 20] Adding Firebase support to useAuth, pt2

    Firebase continues to be πŸ’©. No wonder people keep asking for support in useAuth. Almost there ✌️

    SSR, SSRwR, SSG, CSR, WTFBBQ???

    These abbreviations are getting out of hand. It's like a bad interviewer's wet dream.

    Use private libraries to cleanup your codebase

    You're using the many-small-repositories approach to work faster as a team. But where do you put shared code? How do you make it nice to use? How to publish and install private packages?

    React context without context, using XState – CodeWithSwiz 14, 15

    useAuth works without React Context! πŸŽ‰ here's how

    Swap useReducer with XState – CodeWithSwiz 13

    In Refactoring a useReducer to XState we talked about a 5 step process to turn a reducer into an XState state machine. Today answers "Ok now what?"

    Prefetch data with React Query and NextJS – CodeWithSwiz 8, 9

    Prefetching lets you start React apps without loading spinners. Gatsby introduced this concept with `staticQuery`, react-query and NextJS make the pattern easier 😍

    Modern backend is a JavaScript function

    Many engineers think server-side code is the scary domain of True Engineers. Something newbies, juniors, and frontend engineers shouldn't touch. They're wrong. Modern backend is a joy. ❀️

    Using JavaScript to commit to Github – CodeWithSwiz 7

    Update code with a JavaScript function? Easier than you think 😍

    Why NextJS /api routes are fab – CodeWithSwiz 6

    In this episode of CodeWithSwiz, we tried NextJS's support for /api routes – code running on the backend. In a word – Wow

    Exploring NextJS with a headless CMS, pt4 – CodeWithSwiz

    NextJS getStaticProps, environment vars, and why you shouldn't use yarn link – all in this episode of #CodeWithSwiz

    Exploring NextJS with a custom CMS, pt3 – CodeWithSwiz

    Friend, this episode of #CodeWithSwiz was a great example of why you want to start using TypeScript and how thermal load *destroys* computers.

    Building a small CMS with NextJS, pt2 – CodeWithSwiz

    You're the computer, the CMS is your script. Starting small, trying NextJS, comparing microbundle vs. parcel for extracting libraries out of projects.

    Your first NextJS app – CodeWithSwiz

    On CodeWithSwiz ep2, we tried NextJS and built our first tiny app. Complete with a design system, static rendering, React Query to talk to AWS Lambda, and deployed to live 🀘

    CodeWithSwiz: Privacy-focused embeds for YouTube, Twitter, et al

    A new old experiment πŸ‘‰ regular livecoding. It's like a podcast with video, show notes, regular cadence, and we both learn something new.

    In 2020's, what is "frontend"? 🀨

    "He's a frontend guy, is this even a fair question to ask?" The head of engineering was worried about our systems design question …

    Why you should build a form generator

    Lemme guess, every project involves 1 or 2 forms and they're all the friggen same. You got forms coming out the wazoo. Render fields. Connect to state. Add field validation. Detect submit. Add form validation. Send fetch request. Repeat.

    How you can start using GraphQL today without changing the backend

    GraphQL for new projects looks great ... buuuut how do you use it with that old backend cobbled together in Rails over the last bazillion years?

    How GraphQL blows REST out of the water

    Let's have a look at hyow GraphQL makes queries so much easier and more pleasant than REST

    Is hot dog taco?

    What if I told you modern tools let you build and launch a small webapp in 30 minutes? Complete with SSL, a .com domain, a database, a documented API, CDN hosting, fast static initial loads, and a hydrated SPA? That's the challenge I posed at Silicon Valley Code Camp this weekend. The audience didn't believe me, so it was time to perform some magic. πŸ§™

    REST API best practice in a GraphQL world

    GraphQL is taking the world by storm and it is wonderful. But in the real world, you're still dealing with REST APIs aren't you?

    The Big Mac index and Jest fetch testing

    The Big Mac index is a purchasing power parity index published by The Economist. Jest fetch testing is a tech task so frustrating that it almost made me quit the industry. I'm writing this so you don't have to read 8234721 different blog posts, stack overflow answers, and GitHub threads with conflicting info on how to get Jest and fetch to play together.

    TypeScript for serverless lambda backends πŸ‘Œ

    A few months ago I inherited a Kotlin project. It was an unfinished prototype and all I had to do was wrap it up and deploy. Every time I touched the project, it broke. Nothing worked. Wouldn't run on my machine, wouldn't read API requests, couldn't get tests working, if I changed some code I broke it all. That's when I realized learning a new field is super hard

    Just for fun πŸ‘‰ React vs. jQuery vs. Svelte, same 🐱 app

    I was bored Monday night and decided to see if I still know how to build with jQuery. Nothing better to do, no pressing ideas, a bit of fun. Also a favor for a friend who's preparing to talk about React to a bunch of people who've never seen it before πŸ˜›

    LOLCODE-to-JavaScript compiler babel macro

    A fully functioning LOLCODE-to-JavaScript compiler implemented as a Babel macro. You never thought you wanted this and now here it is. You're welcome. 🐱

    Finally, a practical use case for JavaScript generators!

    JavaScript generators are amazing. They let you write infinite loops that terminate. Yield values from functions before they finish … and I bet you've never used a JavaScript generator even once did you? I FOUND A USE! A real world practical use-case where generators make your code better. 😱

    You don't want to build your own list virtualization

    Chatroom is slow? I know, I'll just use list virtualization! List virtualization is hard, dear reader. So, how do you virtualize a list?

    How to add real web push notifications to your webapp

    You've probably seen web notifications before. YouTube shows them when it goes to a new song, Facebook pings them when a new message comes in, scammy websites ask for permissions and you say no. The usual. You can fire those notifications from anywhere inside your JavaScript.

    JavaScript promises are just like monads and I can explain both in less than 2 minutes

    There's a joke in functional programming that once you understand monads, it becomes impossible to explain them to others. The nuance is nuanced, the details are hard, let’s focus on practice

    How JavaScript linters cause bugs

    I was doing code review for a coworker, and it soon became obvious that he used a linter and that the linter gave him a bright idea: _use strict comparisons_.

    Counting web sessions with JavaScript

    How many touch points does your sales process require? Do you need 2 ad clicks or 5? Two shiny demos or one fat video? As an engineer, you might not care, but this is the stuff that keeps your CEO and growth lead and head of product up at night. A business owner that can answer that πŸ‘† question reliably is god.

    How to waste hours of life with fetch() and a bit of brainfart

    Both superagent and fetch() enable you to talk to a server. The first produces clean code that gets nesty if you need many things. The second produces clean code that is Promis-y and sometimes cumbersome. The difference between superagent and fetch() isn't that one sends your headers as-given and the other lowercases their names. The difference is that superagent sends a cookie and fetch() doesn't!

    A puzzle in JavaScript objects

    This is a puzzle you can run into if you’re not careful, and sometimes, despite your best efforts, even if you are careful. It happened to me when I had a settings object that I passed into a view. The view then did things. When I made a new view from the settings object, it looked like the view I had just cleared.

    A day is not 60*60*24 seconds long

    Days aren't 60*60*24 seconds long. They are 1 day long, which on most days maps to 60*60*24 = 86400 seconds. But not on all days.

    Javascript debugging [slightly] beyond console.log

    My favourite tool for javascript debugging is `console.log`. I mean, I love `console.log`. If I ever get a programming tattoo, it's going to be `console.log` or some variation thereof. Simple to use, works every time, and every programming language I've used since I was 9 has had some variation of it.

    My new favourite Javascript trick

    Using returns and callbacks in the same function. Sounds like crazy talk I know, but hear me out, I have good reason. I think.

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