Dillon Mulroy λ
@dillon_mulroy
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domains guy @vercel ▲ • tweets about functional programming, typescript, neovim, & formula 1 • https://t.co/6Vr6DiQmze • https://t.co/4c0WNBRDIp
Joined October 2011
real talk, dillon really is one of the most talented engineers to follow on twitter. do it. follow him now.
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this is what peak software engineering looks like, i dont make the rules
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just failed an interview for a typescript dev position b/c i don't know what something called useState is :(.
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i have joined the 1 monitor club. before and after
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hey. don’t do this this or be like this guy. 1. don’t be an asshole, just a good goal in life. 2. don’t ruin future opportunities. it might be edgy and funny on twitter, but it if i found this for a candidate i was interviewing for my team (and i would), it’d be an immediate.
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this is what happens when you keep your engineers out of pointless meetings and give them trust and autonomy. they ship.
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.then and .catch are a better api than async/await with try/catch and you can't change my mind.
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you can take advantage of the fact that javascript maps preserves their keys in insertion order to build a really simple LRU cache in 40 lines of code. don't npm install the world
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how do you if there's a functional programmer on your team?. there will be signs
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i thought this was a @terminaldotshop ad at first.
Freddie Mercury having a sleepover with some close friends. Circa 1980
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i once crashed an on prem bitbucket server for multiple days by committing an emoji.
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If I had any wisdom to teach younger devs it would be this:. 1. Program against, consider, and handle the error path first and foremost. Include useful logging, telemetry, and error messages. 2. Utilize your type system, whatever that may be, to make as many invalid states.
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i’d rather have no unit tests than unit tests that are simply testing a bunch of mocked dependencies. just creates tech debt and patterns/code others will mindlessy copy.
are you testing the code or the mocks brother.
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type systems
Which strongly-typed functional language are you using?.
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it breaks my heart to think of all the millions of cpus and petabytes of ram fully dedicated to running eslint in ci/cd . eslint has cost the world more than null.
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they don't teach this kind of big brain strategy in college
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Vim and Neovim users on OSX, set this in Keyboard settings and thank me later
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chatgpt o1-mini randomly started reasoning in chinese this morning. i've never input any sort of chinese text or cultural references before. 🤔
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Woops! Despite doing everything by the books and not using any escape hatches ('as', 'any', or 'non-null assertions') TypeScript let us give a normal 'member' admin permissions! 💥
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I was firmly in the merge > rebase camp for over a decade(!) and preached "why add complexity and risk!?" . I took an hour one day to really learn about rebase and I've completely flip flopped and actually find merge commits fundamentally more confusing and hard to work with.
Rebase is based. Feat @ThePrimeagen .
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Forget Tailwind. Forget utility classes. You have no idea what’s coming. Forget everything you know. Forget everything you think you know. Forget Bootstrap. Forget Foundation. Nothing can prepare you for what my friend saw someone talking about and described to me. If you.
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Did you know Array.from accepts a second argument for mapping over your data? Super useful for making test data sets.
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typescript/javascript happy path blindness is real. go through a critical code path in your application and note every single place an error can be thrown. are you handling each appropriately?. we did this with part of our domain renewal flow. from 3 errors to 17
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🌶️ React/TS/JS Hot Take🌶️. One thing that drives me crazy about the React ecosystem, and more specifically "tech influencers" and "thought leaders" in the space, is the infantilization of the developers using and working in it. I’m tired of reading takes like TypeScript.
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i'm old enough to remember that this is just what javascript looked like pre TS/Zod/IoTS/etc.
You don't need @valibot @zodtypes or even @arktypeio. You can just rawdog it and go clinically insane.
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the most important typescript feature is discriminated unions and everyone should be using them more.
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Rust + sqlx is such a nice experience. The query is even type checked at compile time
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there are 3 constants in the universe. 1. death.2. taxes.3. the f# reply guy showing up anytime i mention OCaml.
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Finally landed on a tmux, neovim, and ghostty config + setup I'm super happy with
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Ya know what’s way more important in being a great software engineer than having strong math skills?. Having great catalytic/soft skills. You can be the smartest person on the planet, but if you can’t communicate your ideas, build consensus, and empathize with your stakeholders.
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Lets build the Option<T> type and some helpers for it from scratch in TypeScript!. First, lets define our types
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Over the years I’ve stopped reading the docs and started reading the source more often than not.
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My hot take is that JS has the lowest bar of entry to building and being productive (a good thing) but one of the highest bars of any language and stack to building high quality, stable, and reliable software. Very few devs have the expertise to pull off the latter.
JS ecosystem is weirdly a high judgement required stack. - tons of garbage to dodge.- noise from the amount of VC funding pushing confusion.- infinite solutions for every micro problem tempting their way into your codebase. you really need to be good at finding clarity.
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The anatomy of a good error message from the Wix UX/Eng team. So. Good. 🤌.
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One of my favorite and most used type helpers, UnifyIntersection (also commonly referred to as Prettify)
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I can't think of a language where performing a req/resp cycle, including serializations and deserialization, looks this nice and is as simple as this. Gleam is winning my heart
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echo -n I will be engaged to @justine_cgrove in 10 hours 😁| shasum -a 256.85416d66705fb334964f111c7921a32dc4c9cd0ea80a3e49521e35835c10fb9c -
85416d66705fb334964f111c7921a32dc4c9cd0ea80a3e49521e35835c10fb9c.
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i regret to inform y'all that this is the hard truth. i've become a much more well rounded and experienced dev since starting streaming dev content every morning. There are so many things i'd have never learned or explored without being intentional and working the muscles
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@1owroller yes bro. i haven’t opened my terminal in months. what am i using the terminal for? npm run dev? pip install? make? why would I need a separate piece of software for that it just lives in vscode.
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That time I was trying to verify a JWT in OCaml and found a bug that I thought was in the JWT library, which then lead to thinking there was a bug in OCaml's main crypto library, which then lead to thinking there was a bug in the underlying C library, which then turned into the.
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i successfully tricked a room of 500 typescript/react devs into learning about monads and they didn’t even know it.
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Okay. I've given @EffectTS_ a real shot and built the app below. It concurrently runs several services for communicating with Twitch and Spotify. I can confidently say Effect is a joy to use and will be a core part of my stack going forward. Take aways below 🧵👇
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really digging using namespaces to organize modules and code in typescript
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i responded to devdad privately, but i want to share my take on this publicly. This is what leads to slop JS/TS software. Treating errors generically like this is a mistake. It leads to fragile software, poor telemetry/observability/debugging, and as a result worse experiences.
just rage quit neverthrow. whatever happened to the good ole try/ catch anyway. (dm-ing dmmulroy for help).
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Introducing ts-error-translator.nvim 🚀. A Neovim port of @mattpocockuk's VSCode extension, ts-error-translator, that turns messy and confusing TypeScript errors into plain English. Get it here! .
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Where do y’all normally load these heavy black pans at in your dishwasher? Every angle I try is awkward
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how much soap am i supposed to use when i wash my rice
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the book that cost the Frontend World more than null
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Once again I will repeat: The value of tailwind is not inherently the inline utility classes (though, I am a huge fan), it's the underlying design system and API to access that design system in a common sense and predictable way. It makes doing the right thing easy.
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using typescript enums is fine btw, i promise you’re writing worse code than what is generated for them.
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npm uninstall prettier eslint typescript-eslint && npm install biome.
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why would you use redis when you can use dns txt records.
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If this isn't your answer you're ngmi
how would you reverse an array during an interview?.
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tech im excited for in 2025:. - @EffectTS_ by @MichaelArnaldi and Co. - libghostty by @mitchellh .- Porffor ( by @CanadaHonk .- Picos ( by Vesa Karvonen.- @ladybirdbrowser by @awesomekling .- @gleamlang by @louispilfold and team.
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now would be a great time to start a consultancy/agency specialized in Wordpress to NextJs migrations.
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we can peak harder
like it or not, this is what peak react server components looks like
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sometimes i talk about things i like in front of other people
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yup, decided. i'm ditching nix. i still think that there is no better solution, but i only use a small portion of it and when it breaks its too much work to justify.
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didn’t sleep at all on my flight but got to see this
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@WarrenInTheBuff why'd you dox me and my code like this, i thought this was going to stay private.
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just kidding, now the queen has arrived
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@fasterthanlime my jaw dropped listening to this yesterday. idk how the presenter(s) could have been more clear (and kind!). just in one ear and out the next for that - he was looking for any reason to be a dick about rust.
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I never want to work in a language without pattern matching again
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finally got around to fixing the keybinds on my personal site lol
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@PraveenPerera 1. i'm not crying about it, i'm not even offended. but if this is your idea of fun, it's in complete contrast with your admission of my third point being fair. 2. not sure how that's a threat, just blanket advice that freedom of speech !== freedom of consequences. 3. yup.
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