allowing custom serializer?

[arily]

Hi,
I am using nitro with Nuxt3.
as described in #804, we can only send json to the client.

with nuxt-trpc I am able provide my custom serializer like https://trpc.io/docs/server/data-transformers#different-transformers-for-upload-and-download shows, using superjson when client -> server and uneval in server -> client.

with this approach I am serializing the response to string, then serialize this string to json again with json-rpc overheads.

I am looking for a way to optimize this output, a custom serializer in h3/nitro would be a perfect fit.

is it possible to do something like I described?

[mubaidr]

Right now, if json/ object is returned from the nitro API, there is mismatch on client-side for types. An option to specify custom serializer would be awesome!

Just wondering we already have @nuxt/devalue module, wondering if the same can be used for this purpose?

[arily]

poc
handler.ts

import { uneval } from 'devalue'
import type { EventHandler, EventHandlerRequest } from 'h3/dist/index'

export function defineUnevalEventHandler<TReq extends EventHandlerRequest, TRet>(fn: EventHandler<TReq, TRet>) {
  return defineEventHandler(async (event) => {
    try {
      const returnValue = await fn(event)
      event.node.res.end(uneval(returnValue))
    }
    catch (err: any) {
      event.node.res.writeHead(500)
      const returnValue = JSON.parse(JSON.stringify(err, Object.getOwnPropertyNames(err)))
      const { message = undefined, ...rest } = returnValue
      event.node.res.end(`throw new Error(${uneval(message)}, ${uneval(rest)})`)
    }
  }) as EventHandler<TReq, TRet>
}

server/api/test-safe.ts

import { defineUnevalEventHandler } from '../handler'

export default defineUnevalEventHandler((event) => {
  return {
    article: 'hello world!',
    date: new Date(),
    set: new Set(),
    map: new Map([
      ['key', 'value'],
      ['key2', 'value2'],
    ]),
  }
})

server/api/test-error.ts

import { defineUnevalEventHandler } from '../handler'

export default defineUnevalEventHandler((event) => {
  throw new Error('boom')
})

GET /api/test-safe

{article:"hello world!",date:new Date(1699258213021),set:new Set([]),map:new Map([["key","value"],["key2","value2"]])}

Get /api/test-error

throw new Error("boom", {
    stack: "Error: boom\n    at \u003Canonymous> ...(rest of the stack)"
})