Content is returned as { type: 'Buffer', data: [...] } with $return binding

[zavr-1]

With

import { readBuffer } from '@wrote/read' // returns a buffer

export default async () => {
    const body = await readBuffer('style.css')
    context.res = {
        body,
        headers: {
            'content-type': 'text/css',
        },
    }
}

and bindings

{
  "disabled": false,
  "bindings": [
    {
      "authLevel": "anonymous",
      "type": "httpTrigger",
      "route": "style.css",
      "direction": "in",
      "name": "req",
      "methods": [
        "get"
      ]
    },
    {
      "type": "http",
      "direction": "out",
      "name": "res"
    }
  ]
}

my CSS file is served properly. When I change the bindings to use $return, I get served a buffer in serialised format:

    {
      "type": "http",
      "direction": "out",
      "name": "$return"
    }

import { readBuffer } from '@wrote/read' // returns a buffer

export default async () => {
    const body = await readBuffer('style.css')
    return {
        body,
        headers: {
            'content-type': 'text/css',
        },
    }
}

{"type":"Buffer","data":[46,103,111,111]}

---

Azure Functions Core Tools (2.1.748 Commit hash: 5db2066)
Function Runtime Version: 2.0.12134.0

[mikhailshilkov]

I've hit the same issue today trying to return an image from my function. $return didn't work with a body buffer, while changing it to res worked.