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Mateusz Burzyński

@andarist.bsky.social
5.9K followers 238 following 277 posts

programmer but also a little bit of code-poet wannabe, maintaining XState, Emotion, Changesets, redux-saga & more, OSS enthusiast

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Mateusz Burzyński @andarist.bsky.social · 11/08/2026
Changesets v3 is here! 🦋 After months of chipping away at issues alongside @bluwy.me, @haglund.dev, and many other contributors, we’re excited to finally share it. changesets.dev/blog/announc...
changesets.dev
Announcing Changesets v3 | Changesets
A tool to manage versioning and changelogs with a focus on monorepos
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Reposted by Mateusz Burzyński
Bjorn Lu @bluwy.me · 25/05/2026
We’ve been working on a new site for Changesets with a lot of new docs! If changesets has been confusing before, hopefully some of these will help, or let us know what else could be improved. Check it out 👉 changesets.dev
changesets.dev
Changesets
A tool to manage versioning and changelogs with a focus on monorepos
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Reposted by Mateusz Burzyński
Mark Erikson @acemarke.dev · 19/03/2026
My Replay time-travel-based React+Redux perf reports experiments are coming together! Just nailed sourcemapped component + selector identities, and I've got accurate timing details on dispatches + renders from a Replay DevTools E2E recording! Early perf report example attached.
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Mateusz Burzyński @andarist.bsky.social · 10/12/2025
That’s how we, Polish people, smile
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Mateusz Burzyński @andarist.bsky.social · 25/08/2025
Yesssss github.com/microsoft/Ty...
github.com
Enable `--strict` by default · Issue #62333 · microsoft/TypeScript
Background Almost a decade ago, we began to add certain options beyond --noImplicitAny and --strictNullChecks. Flags like --strictFunctionTypes, --noImplicitThis, and --strictBindCallApply have bee...
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Mateusz Burzyński @andarist.bsky.social · 06/07/2025
Trivia question - how many errors are reported by TS here? (:
declare const test: never;

if ("foo" in test) {
}

test.foo;
test["foo"];
const { foo } = test;
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Mateusz Burzyński @andarist.bsky.social · 04/07/2025
@jakebailey.dev ported my perf-oriented PR to TS-Go and it helps quite a bit (%-wise) there too! This is nice github.com/microsoft/ty...
github.com
Port TS PR 61505 - Cache mapper instantiations by jakebailey · Pull Request #1358 · microsoft/typescript-go
This is an early port of microsoft/TypeScript#61505, because I like to go fast Calculating the key increases allocs by a bit (really wish we had the yet-to-exist Go custom map implementation), but ...
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Mateusz Burzyński @andarist.bsky.social · 23/05/2025
Weird trivia learned while looking through v8's source: function fn(a) { console.log(a) } fn.toString() // 'function fn(a) { console.log(a) }' const bound = fn.bind(null) bound.toString() // 'function () { [native code] }'
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Mateusz Burzyński @andarist.bsky.social · 20/05/2025
People: lockfiles are important! People: uses github/action@v1 Me: uses github/action@v1 🫠
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Reposted by Mateusz Burzyński
Bjorn Lu @bluwy.me · 21/04/2025
A prerelease of Changesets v3 is out! Some code and dependency cleanups so far, with more minor breaking changes soon, but should be simple to upgrade. Thanks to @andarist.bsky.social for helping to make this happen. github.com/changesets/c...
github.com
Release @changesets/cli@3.0.0-next.0 · changesets/changesets
Major Changes #1479 7f34a00 Thanks @bluwy! - Add "engines" field for explicit node version support. The supported node versions are >=18.0.0. #1482 df424a4 Thanks @Andarist! - From now on this ...
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Mateusz Burzyński @andarist.bsky.social · 15/04/2025
@searyanc.dev what's the proper mental model when it comes to void's presence in unions and intersections? and how it should behave when those are narrowed down by CFA etc? I can't find comprehensive answer to this anywhere
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Mateusz Burzyński @andarist.bsky.social · 08/04/2025
I have one bad habit I don't like: I'm trying to fix every issue I find in my node_modules I have one good thing to say about myself: I'm trying to fix every issue I find in my node_modules
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Mateusz Burzyński @andarist.bsky.social · 01/04/2025
Once again I reminded myself how awesome Replay and time-travel debugging is. True game changer - I'd be hunting this bug for hooours without it.
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Mateusz Burzyński @andarist.bsky.social · 26/03/2025
I convinced my wife to get a Macbook...
media.tenor.com
a woman is wearing a black and white suit with the hashtag schitts creek on the bottom
ALT: a woman is wearing a black and white suit with the hashtag schitts creek on the bottom
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Mateusz Burzyński @andarist.bsky.social · 15/03/2025
> Unable to evaluate expression: call is only supported with topmost stack frame 🫠🫠🫠 I hate this sooo much
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Mateusz Burzyński @andarist.bsky.social · 11/03/2025
I have some serious pull requests porting to do 😂 github.com/microsoft/Ty...
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Mateusz Burzyński @andarist.bsky.social · 26/02/2025
I couldn't believe this thing when I first heard about it and I'm truly amazed that Dimitri had so much stubbornness in him that he stuck with it and made it happen
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Mateusz Burzyński @andarist.bsky.social · 22/01/2025
I feel like I'm abusing implementation details of TypeScript just a little bit too much here 🤣 github.com/statelyai/xs...
github.com
[@xstate/store] v3 by davidkpiano · Pull Request #5175 · statelyai/xstate
Actor-based state management & orchestration for complex app logic. - [@xstate/store] v3 by davidkpiano · Pull Request #5175 · statelyai/xstate
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Mateusz Burzyński @andarist.bsky.social · 19/01/2025
I just had to alias `util` to `node:util` using Vite's aliasing option. Life is beautiful
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Mateusz Burzyński @andarist.bsky.social · 12/01/2025
I've intentionally used default case in switch/case on non-last position for the first time in my life, AMA github.com/thysultan/st...
github.com
Fixed `@left-*` parsing by Andarist · Pull Request #342 · thysultan/stylis
fixes #341
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Mateusz Burzyński @andarist.bsky.social · 11/01/2025
This was an interesting dive for me into how TS constructs its control flow information, I played a couple of times with interpreting its pieces in the narrowing-related code, but I almost never had a need to change how its created: github.com/microsoft/Ty...
github.com
Fixed an issue with for statement's incrementor missing continue's control flow information by Andarist · Pull Request #60950 · microsoft/TypeScript
fixes #60945
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Mateusz Burzyński @andarist.bsky.social · 01/01/2025
I had it lying on my machine since August, it's time to tie 2024's loose ends 😅 so I finally got myself to push it out and open a PR cc @colinhacks.com @ssalbdivad.dev @effect-ts.bsky.social github.com/microsoft/Ty...
github.com
Add support for JSDoc `@ignore` to allow for hiding properties from completions by Andarist · Pull Request #60895 · microsoft/TypeScript
closes #47613
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Mateusz Burzyński @andarist.bsky.social · 30/12/2024
JS class private fields trivia #1 - you can access them in subclasses as long as those subclasses are defined within the superclass
class Test1 {
  #priv = 10;

  Foo = class Foo extends Test1 {
    constructor() {
      super();
      console.log(this.#priv);
    }
  };
}

const t1 = new Test1();
new t1.Foo(); // logs: 10
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Mateusz Burzyński @andarist.bsky.social · 17/12/2024
OSS is weird, I maintain packages that I don't even use at all nowadays
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Mateusz Burzyński @andarist.bsky.social · 10/12/2024
nice experimentation by @jfet97.bsky.social going on: github.com/microsoft/Ty...
github.com
Let primitive types discriminate a union of objects by jfet97 · Pull Request #60718 · microsoft/TypeScript
Main goal The ultimate goal of this PR is to allow primitive types in object unions to act as discriminants, even when there are no unit/literal types involved. Some examples of this are as follows...
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Mateusz Burzyński @andarist.bsky.social · 03/12/2024
I'm supposed to be good at TypeScript but typing generic wrappers around React.forwardRef is... 🫠
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Mateusz Burzyński @andarist.bsky.social · 29/11/2024
Inspired by @tkdodo.eu, I opened a PR with a codefix proposal to add "missing" awaits into return statements in async function enclosed by try statements github.com/microsoft/Ty...
github.com
Implement codefix for adding missing `await` in `return` statements enclosed by try statements by Andarist · Pull Request #60642 · microsoft/TypeScript
Given that async functions flatten returned promises it's a fairly easy mistake to make to assume that try/catch/finally enclosing a returned promise can handle that as if return await p would ...
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Mateusz Burzyński @andarist.bsky.social · 27/11/2024
Like it or not, this is how art is born
A list of commits on GitHub, all with "wip" commit message and failed CI checks
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Mateusz Burzyński @andarist.bsky.social · 15/11/2024
I'm reading v8 source code to understand how promises are created and chained internally... what my life has become
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Reposted by Mateusz Burzyński
Sentry @sentry.io · 12/11/2024
We Just Gave $750,000 to Open Source Maintainers 🥳 blog.sentry.io/we-just-gave...
blog.sentry.io
We Just Gave $750,000 to Open Source Maintainers
In honor of the 4th year of our Open Source Pledge, we’re excited to continue driving this important conversation. See what we’ve accomplished in 2024 here.
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Mateusz Burzyński @andarist.bsky.social · 06/11/2024
And btw... this was shipped by one and only @gabritto.bsky.social
bsky.app
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Mateusz Burzyński @andarist.bsky.social · 06/11/2024
I'll remember the world before and after this PR: github.com/microsoft/Ty... The new era of conditional types checking is coming in TypeScript 5.8!
github.com
Narrow generic conditional and indexed access return types when checking return statements by gabritto · Pull Request #56941 · microsoft/TypeScript
Fixes #33912. Fixes #33014. Motivation Sometimes we want to write functions whose return type is picked between different options, depending on the type of a parameter. For instance: declare const ...
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Mateusz Burzyński @andarist.bsky.social · 03/11/2024
I still find surprising type behaviors in TypeScript. This one makes sense but I had to think about it for a moment to understand how it can be explained: www.typescriptlang.org/play/?ts=5.7...
typescriptlang.org
TS Playground - An online editor for exploring TypeScript and JavaScript
The Playground lets you write TypeScript or JavaScript online in a safe and sharable way.
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Mateusz Burzyński @andarist.bsky.social · 03/11/2024
Filip cooked something really nice here
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Mateusz Burzyński @andarist.bsky.social · 02/11/2024
My PR adding support for package.json#imports in import statements got merged in recently. I think it made the cut for 5.7 just before the RC so it will be in the final release! github.com/microsoft/Ty...
github.com
Add string literal completions for `package.json` `imports` field by Andarist · Pull Request #57718 · microsoft/TypeScript
closes #52460 closes #57680 closes #57777 Currently, this only has tests based on #55015 but I still have to add more
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Reposted by Mateusz Burzyński
delba @delba.bsky.social · 01/11/2024
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Mateusz Burzyński @andarist.bsky.social · 31/10/2024
This looks neat ✨
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Mateusz Burzyński @andarist.bsky.social · 30/10/2024
Wow, this got busy. I’m not even using this app (yet?) and I see an influx of hundreds of new followers in the past days
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Mateusz Burzyński @andarist.bsky.social · 06/05/2023
Partial inference through _ sigil at call site got scheduled for TS 5.2 🎉 github.com/microsoft/TypeScript/pul…
github.com
Implement partial type argument inference using the _ sigil by weswigham · Pull Request #26349 · microsoft/TypeScript
In this PR, we allow the _ sigil to appear in type argument lists in expression positions as a placeholder for locations where you would like inference to occur: const instance = new Foo<_, string>...
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Mateusz Burzyński @andarist.bsky.social · 24/04/2023
Lol, this thing has no giphy integration yet. How do they even dare to call this a product
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