TypeScript Go support (at least in CLI)

[notramo]

Description

JSX support has been recently implemented in the Go implementation of TypeScript.

The new Go implementation is a lot faster (10 times faster in some projects), and uses ~half the memory as the JS implementation.

It seems that this new version has enough features for a fast CLI svelte-check command. LSP support is lacking at the moment, but an optional svelte-check config option would be really useful.

Proposed solution

Add a command line option to svelte-check that enables the use of tsgo tsc … instead of tsc.

Alternatives

None. This seems a quite simple change, with the most obvious solution being a CLI option. Other solutions seem a lot more complicated.

Additional Information, eg. Screenshots

No response

[jasonlyu123]

No. It's not a simple change. svelte-check does not call tsc by the command. It used low-level typescript API that is about to be rewritten in typescript go. This is definitely on the radar but not anytime soon.

[KieranP]

The first Typescript Native Previews just released, and with it a very early version of the APIs:

• https://devblogs.microsoft.com/typescript/announcing-typescript-native-previews/#api-progress
• Scaffold IPC-based API microsoft/typescript-go#711

I understand that it won't be anywhere ready for use by Svelte, but it might be a good time for the Svelte language-tools team/contributors to give the TS team feedback so that APIs support what Svelte needs from day one.

[jasonlyu123]

To keep the expectation in check, TypeScript mentioned a while ago that the TypeScript API library is expected to be released after TypeScript 7 is released. So this most likely won't be available on day one.

[Kae7in]

Really looking forward to this, especially in our SvelteKit app where we have ~370K LoC in .svelte files and svelte-check takes about 54s :(