Just launched Onion.JS based on HotScript 🙌

[ThomasAribart]

Hey @gvergnaud !

Just wanted to let you know that I released a middleware library called OnionJS base on your awesome work on HotScript 🙌

It's a library that allows dev to build and apply middlewares/high-order functions in a type-safe way:

import { Onion, Layer } from '@onion.js/core'
import type { Objects } from 'hotscript'

const jsonStringifyBody: Layer<
  Record<string, unknown>, // subject type
  Objects.Update<'body', string>, // outward HO Type
  Objects.Update<'body', unknown> // inward HO Type
> = before => {
  const after = {
    ...before,
    body: JSON.stringify(before.body)
  }

  return after
}

// Either wrap a `before` to output an `after`
const before = {
  headers: null,
  body: { foo: 'bar' }
}

const after = Onion.wrap(before).with(jsonStringifyBody)
//      ^? { headers: null; body: string } 🙌

// ...or start from an `after` + layers and deduce the `before` type
const after = Onion.produce<{ headers: null; body: string }>()
  .with(jsonStringifyBody)
  .from({ headers: null, body: { foo: 'bar' } })
//   ^? ({ headers: null; body: unknown }) => { headers: null; body: string } 🙌

It's really awesome and it couldn't have existed without HotScript so thank you ❤️

I'm already using it on my projects, and am planning on publishing ready-made middlewares (like middyJS) so will probably create some PRs here as well :)

Cheers,

Thomas