SWC Plugin

[stnwk]

Next.js seems to be switching from babel to swc, see: vercel/next.js#29811

In the next stable release, swc will be used by default to compile a Next.js project if there is no custom babel.config.js, with the goal to eventually completely drop support for babel.

I guess this means, there will be a need for a superjson-swc plugin of some sort? babel-plugin-macro is having a similar discussion about it here: kentcdodds/babel-plugin-macros#144

What are your thoughts?

[Skn0tt]

Thanks for opening this issue! Given Next's typical behaviour around deprecations, I don't see this as something we immediately have to act on. But I definitely see the need for an SWC plugin!

Warning: Plugin apis are going to be deprecated in v2. With v2, swc will provide a rust-based plugin api instead.
~ SWC Docs

Given that status, I propose to wait until SWC v2 is released.

[flybayer]

@Skn0tt you can already use the Rust plugin APIs. Next.js is using them.

Here's the source for the next.js plugins: https://github.com/vercel/next.js/tree/canary/packages/next/build/swc/src

We definitely want an swc version of this. We're going to be writing rust version of our other blitz plugins too.

[flybayer]

I managed to get more information from the Vercel team:
https://twitter.com/flybayer/status/1454547398521393153

TLDR: There are no docs for SWC plugins because there is not yet an official SWC Rust plugin API.

The SWC Rust plugin API is starting to be worked on now.

So not much we can do for now.

[elie222]

warn - Disabled SWC as replacement for Babel because of custom Babel configuration ".babelrc" https://nextjs.org/docs/messages/swc-disabled

A quick fix would just be to manually use this package when needed instead of relying on Babel to do it, right?

[flybayer]

@elie222 correct

[elie222]

Ah, just tried it: superjson.serialize().json means you lose the TS types. will pass for now :(

[CanKattwinkel]

Ah, just tried it: superjson.serialize().json means you lose the TS types. will pass for now :(

Then you might want to wrap all your props simply with

type Serialized<T> = {
    [P in keyof T]: T[P] extends Date ? string : Serialized<T[P]>
};

Disclaimer: this might need to be extended to cover any object structure, js data type.

[remorses]

I made a nextjs plugin that does not disable the SWC transform

You can try it here

Basically it applies the superjson babel plugin only on the pages files, without adding a .babelrc file

[Skn0tt]

Putting this here for anybody who comes across this issue: @remorses's plugin, while not adding a .babelrc file, still uses Babel. I consider this to be a work-around, the real goal will be to create an SWC equivalent of babel-plugin-superjson-next.

[elie222]

Does it matter if it’s using Babel if SWC works? Or are we still seeing slow builds because of it. I’ve started using remorses package. Best, Eliezer

…

On Mon, Nov 22 2021 at 9:57 AM, Simon Knott < ***@***.*** > wrote: Putting this here for anybody who comes across this issue: @remorses ( https://github.com/remorses ) 's plugin, while not adding a.babelrc file, still uses Babel ( https://github.com/remorses/next-superjson/blob/959b3dc6063976ac2298a86b7169e38034b7bcbe/next-superjson/src/index.ts#L25 ). I consider this to be a work-around, the real goal will be to create an SWC equivalent of babel-plugin-superjson-next. — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub ( #157 (comment) ) , or unsubscribe ( https://github.com/notifications/unsubscribe-auth/AAXSQXYIMPIWTW5HSTWHK7LUNHZXNANCNFSM5GTQEOPA ).

[Skn0tt]

It will introduce another bundler into the pipeline, which will slow things down, yes. It won't be as big of a slowdown as the full-on babel strategy which happens when there's a .babelrc (this will fully disable SWC, and use Babel for everything), but I suspect it's noticeably slower. It's also somewhat of a weird setup, where code goes through two transpilers (first babel, then SWC); and I suspect that this is not officially unsupported by Next.js. Maybe @timneutkens can shed some light.

[remorses]

@Skn0tt the Babel plugin only runs on the pages directory, this can’t be a performance problem unless you have a page 10k lines long

[Skn0tt]

That's a good point @remorses! Thank you, I missed that.

Any updates on this?

[kevinsimper]

Could this be solved by using Next.js new middleware? That seems like a possible solution, adding superjson to all responses and then if one wants to use superjson in the component, they need to call superjson.parse?