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Mateusz Burzyński

@andarist.bsky.social

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...

github.com

August 25, 2025 at 6:28 PM

Mateusz Burzyński

@andarist.bsky.social

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;

July 6, 2025 at 8:55 AM

Mateusz Burzyński

@andarist.bsky.social

@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...

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 ...

github.com

July 4, 2025 at 11:53 AM

Mateusz Burzyński

@andarist.bsky.social

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] }'

May 23, 2025 at 12:32 PM

Mateusz Burzyński

@andarist.bsky.social

People: lockfiles are important!
People: uses github/action@v1
Me: uses github/action@v1

🫠

May 20, 2025 at 10:06 PM

Reposted by Mateusz Burzyński

Bjorn Lu

@bluwy.me

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...

Release @changesets/[email protected] · 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 ...

github.com

April 21, 2025 at 12:36 PM

Mateusz Burzyński

@andarist.bsky.social

@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

April 15, 2025 at 9:24 PM

Mateusz Burzyński

@andarist.bsky.social

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

April 8, 2025 at 10:52 AM

Mateusz Burzyński

@andarist.bsky.social

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.

April 1, 2025 at 9:01 PM

Mateusz Burzyński

@andarist.bsky.social

I convinced my wife to get a Macbook...

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

media.tenor.com

March 26, 2025 at 10:53 AM

Mateusz Burzyński

@andarist.bsky.social

> Unable to evaluate expression: call is only supported with topmost stack frame

🫠🫠🫠

I hate this sooo much

March 15, 2025 at 1:49 PM

Mateusz Burzyński

@andarist.bsky.social

I have some serious pull requests porting to do 😂
github.com/microsoft/Ty...

March 11, 2025 at 2:47 PM

Mateusz Burzyński

@andarist.bsky.social

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

MichiganTypeScript @michigantypescript.com · Feb 26

Doom now runs in @typescriptlang.org types. What a journey this one's been.

the famous "ULTIMATE DOOM" poster, but it says "TYPESCRIPT TYPES"

February 26, 2025 at 3:56 PM

Mateusz Burzyński

@andarist.bsky.social

I feel like I'm abusing implementation details of TypeScript just a little bit too much here 🤣
github.com/statelyai/xs...

[@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

github.com

January 22, 2025 at 10:59 AM

Mateusz Burzyński

@andarist.bsky.social

I just had to alias `util` to `node:util` using Vite's aliasing option. Life is beautiful

January 19, 2025 at 10:53 PM

Mateusz Burzyński

@andarist.bsky.social

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...

Fixed `@left-*` parsing by Andarist · Pull Request #342 · thysultan/stylis

fixes #341

github.com

January 12, 2025 at 7:57 PM

Mateusz Burzyński

@andarist.bsky.social

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...

Fixed an issue with for statement's incrementor missing continue's control flow information by Andarist · Pull Request #60950 · microsoft/TypeScript

fixes #60945

github.com

January 11, 2025 at 11:10 AM

Mateusz Burzyński

@andarist.bsky.social

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...

Add support for JSDoc `@ignore` to allow for hiding properties from completions by Andarist · Pull Request #60895 · microsoft/TypeScript

closes #47613

github.com

January 1, 2025 at 12:03 PM

Mateusz Burzyński

@andarist.bsky.social

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

December 30, 2024 at 4:45 PM

Mateusz Burzyński

@andarist.bsky.social

OSS is weird, I maintain packages that I don't even use at all nowadays

December 17, 2024 at 9:13 AM

Mateusz Burzyński

@andarist.bsky.social

nice experimentation by @jfet97.bsky.social going on: github.com/microsoft/Ty...

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...

github.com

December 10, 2024 at 4:31 PM

Mateusz Burzyński

@andarist.bsky.social

I'm supposed to be good at TypeScript but typing generic wrappers around React.forwardRef is... 🫠

December 3, 2024 at 8:55 PM

Mateusz Burzyński

@andarist.bsky.social

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...