Mattia Crovero

Code ideas @ UjibooSrl

[Mattia Crovero @mcrovero]

I’ve been working on an @EffectTS_ package to make it easier to use Effect in the @nextjs App Router world by providing "effectful" wrappers and middlewares. 🚀

Try it out and give early feedback at:

https://t.co/j1GrcdzuyY

[Mattia Crovero @mcrovero]

@berenddeboer Llms are really getting good at Effect, glad you’re enjoying it, any feedback is more than welcome!

[Effect | TypeScript for the AI Era @EffectTS_]

Effect + Next.js: Managed Runtimes, Middleware, DX Improvements

By Mattia Crovero @mcrovero | Effect Milan 2025

https://t.co/KQ8MoalrQf

[Mattia Crovero @mcrovero]

Thanks again to the @EffectTS_ team for the amazing meetup in Milan yesterday, it was great meeting everyone! looking forward to the next event

[Effect | TypeScript for the AI Era @EffectTS_]

Kicking off our first Effect Meetup in Milan 🇮🇹

[Mattia Crovero @mcrovero]

eslint is not a fan of the https://t.co/NeeIyZUkGs name choice

[Mattia Crovero @mcrovero]

@TimZolleis @EffectTS_ yes! it's flexible enough for many use cases. at the end of the day it’s just an effect runner that forwards the args and enriches the errors but it's nice because you can use Effect.fn in framework-exposed handlers and get error tracing + automatic spans for free

[Mattia Crovero @mcrovero]

I’m looking for the smallest helper to start using @EffectTS_ in a Next.js project.. here’s what I came up with so far

[Mattia Crovero @mcrovero]

https://t.co/d47vZdcMDh

Here's the full code

[Mattia Crovero @mcrovero]

@MattiaManzati @EffectTS_ 🤯 this is insane, good job! I tried the vscode extension to see effect spans but I feel like vscode is really limiting ui, is there a web version exposed when starting the dev server? With other features like this one it can be really useful to have them in a web gui

[Mattia Crovero @mcrovero]

@ditorodev @EffectTS_ @nextjs @MichaelArnaldi @kitlangton for now it's a server only library. so for typed client/server communication you’d still need to encode/decode manually. but it would be really nice especially for server actions, maybe even integrated with something like effect-atom from @tim_smart

[Mattia Crovero @mcrovero]

I’ve been working on an @EffectTS_ package to make it easier to use Effect in the @nextjs App Router world by providing "effectful" wrappers and middlewares. 🚀

Try it out and give early feedback at:

https://t.co/j1GrcdzuyY

[Mattia Crovero @mcrovero]

@ditorodev @MichaelArnaldi @EffectTS_ route handlers are coming next! But you can also check out @ethanniser’s examples to achieve it the vanilla way https://t.co/tE8FHtlUrZ

[Mattia Crovero @mcrovero]

@ethanniser @EffectTS_ @nextjs but the idea is to provide a tracer with the current nextjs request span as parent span

[Mattia Crovero @mcrovero]

So good.. free end-to-end tracing thanks to @EffectTS_ and @nextjs automatic spans

[Mattia Crovero @mcrovero]

@ethanniser @EffectTS_ @nextjs the screenshot comes from https://t.co/neujwXaHn2
but it is using my library, i'm working on a vanilla example.

[Mattia Crovero @mcrovero]

@frederic_ooo @EffectTS_ @nextjs Just don’t leave the unattended for too long 😂

[Mattia Crovero @mcrovero]

@matodev @EffectTS_ @nextjs yes but the stacktrace is enriched by the library to include effect's one. you can still improve it by giving names to generator functions

[Mattia Crovero @mcrovero]

Actually enjoying working with @EffectTS_ and @nextjs.

Check out the example repo below 👇

[Mattia Crovero @mcrovero]

@AndersonAndrue Unfortunately Effect.fn cannot infer the type from the build handler, you'd need to specify the type every time like `Effect.fn(function* ({ searchParams }: EffectNextParams) {`, right now you can use middlewares to add spans

[Mattia Crovero @mcrovero]

@elie2222 Yes, that’s true, but how do you know what errors you’ll get and where? You’d need to add something like neverthrow, but then with zod, p-retry, etc., it turns into library sprawl that you could instead standardize with a single package

[Mattia Crovero @mcrovero]

@sa_khan12 @dillon_mulroy @EffectTS_ @nextjs theme: vercel
https://t.co/jUsSxMjDR9