[bananapub]

> I keep hearing about Svelte's flavor of JS basically being its own language now and it not playing all that well with Typescript

it's a weird habit on HN to refer to random rumours that have discouraged you from trying something, and then explicitly not link to even the source of the random thing you're thinking of.

I would guess you're misremembering something about the *developers of Svelte* saying they didn't think Typescript was worth it for *developing libraries*, and so they were switching to using JSDoc annotations for developing Svelte, which has no impact at all on Typescript or Svelte or Svelte users using Typescript?

e.g. https://devclass.com/2023/05/11/typescript-is-not-worth-it-f...

anyway, Svelte is fairly similar to Vue, just a subjectively slightly nicer style. do both tutorials and see which you like I guess?

[rco8786]

> it's a weird habit on HN to refer to random rumours that have discouraged you from trying something, and then explicitly not link to even the source of the random thing you're thinking of.

I don't know about you, but I don't keep a map of "random thought" to "url" anywhere. It seems totally fine/normal in a discussion forum to say "Hey i heard this thing, any substantiation to it?" without needing a source.

[phist_mcgee]

Gonna need a source on why you think that bud.

[johnfn]

But Svelte obviously doesn't play well with TypeScript, and is kind of its own language - you don't need a source for that. Good luck e.g. getting reactive declarations to play well with TS's type narrowing or null analysis.

[npn]

you clearly don't know what you are talking about.

reactive declarations do not change the type of the objects. it just that they can rerun when the dependencies change.

sure for the convenience of the users you do not need to type `let vars...` for every new variable declared in the reactive statement, but no one forbid you to write it before hand, or let the language server/plugin do it for you.

but Svelte indeed do not work perfectly with typescript, because it allows you to write code inside html template, which currently only support javascript expression.

[Volundr]

Data-point of one, but I have definitely run into issues where Typescript can't understand what's going on in a reactive expression, and had to aggressively refactor my code to make everything happy. Most of the time it works great, but when it doesn't it can be really annoying. I wouldn't go so far as to say it doesn't play well, but the seams are definitely visible.

[npn]

Could be the plugin was broken somehow. Happen all the time for me. Even now the syntax highlighting and code formatting feature would break if I write the code the wrong way.

from my understanding the plugin does some clever tricks like insert some dummy code or create some dummy files to be consumed by the typescript language server. so it is not guaranteed to be correct 100% of the time.

[MrJohz]

I mean, that sounds like a data point of two now to me - you're also saying that Typescript and Svelte don't play that nice together if the plug-in breaks "all the time" and you need to be careful how you write code just to get correct syntax highlighting and code formatting, no?

[npn]

Syntax highlighting and code formatting sometime break because Svelte file is single file component format, which mean it has script, markup and style in a single file. It's rather complex to parse it right, especially when you use regexes to do the job like in VS Code.

It's just the problem with the VS Code Svelte extension, not the framework itself nor because of Typescript. Also for my case, it happens because I prefer to not use semicolons in my code, not because it is typescript.

[johnfn]

This simply isn't true. For instance, if you narrow a variable from `1 | 2 | 3` to `1 | 2`, then trigger a reactive declaration, the reactive declaration can't understand that you've narrowed the variable, and you lose that information. Same thing happens if you go the opposite direction and broaden a variable. TS assumes that program flow roughly goes from top to bottom; if you break that invariant you lose a lot of handy features.

> you clearly don't know what you are talking about.

huh?

[OJFord]

I think the claim is that it breaks TS parsing, not that it changes the type.

[npn]

Then it's wrong too. Because it is perfectly valid js code. It is just that they repurpose the label syntax (used for breaking out of inner loops) for the reactive statement.

[losingthefight]

I couldn't disagree more. Compared to the mess of hooks in React, Svelte is closer to JavaScript in the script portion and closer to normal html in the markup portion. I use vite and TypeScript with each project and never once had a typing issue. Ive built several production apps and consider it far better for my brain than other libraries I tried, and I've been using React since before Redux was mainstream. Svelte is my go to now.

[johnfn]

> I couldn't disagree more. Compared to the mess of hooks in React, Svelte is closer to JavaScript in the script portion and closer to normal html in the markup portion.

Come now. Only one of React and Svelte needs a custom compiler to run in the browser, and it isn't React...

[croes]

https://svelte.dev/blog/svelte-and-typescript

[nailer]

I literally hack on TS 5 on Svelte all day and have for a year now (was 4.x originally). Never had a problem with reactive declarations.