Remove the deprecated addToBody option and return files as buffers wh…

…en attachFieldsToBody is set to keyValues (#481)

* Return buffers directly when `attachFieldsToBody` is set to `'keyValues'` (#468)

* return buffer directly

* add test

* move tap path to taprc

* update README.md

* typo

* refactor keyValues handler

* use already set variable

* use for...of

* ditch for...of for Arrays

* use keys rather than entries

* Remove legacy addToBody and callback API (#465)

* remove deprecated method

* remove unused package

* revert modification

* remove addToBody documentation

* remove request.multipart type

* remove legacy comment

* Use for loop for arrays and fix schema option for `keyValues` (#474)

* only add schema when attachfieldstobody is true

* fs/promises

* use `for` for arrays

* conditionally call Object.values

* fix lint

* Update test/multipart-attach-body.test.js

Co-authored-by: Frazer Smith <frazer.dev@outlook.com>

* Update README.md

Co-authored-by: Frazer Smith <frazer.dev@outlook.com>

---------

Co-authored-by: Uzlopak <aras.abbasi@googlemail.com>
Co-authored-by: Frazer Smith <frazer.dev@outlook.com>

.taprc

@@ -1,4 +1,3 @@
-ts: false
-jsx: false
-flow: false
 check-coverage: false
+files:
+  - test/**/*.test.js

README.md

@@ -22,8 +22,6 @@ npm i @fastify/multipart
 
 ## Usage
 
-If you are looking for the documentation for the legacy callback-api please see [here](./callback.md).
-
 ```js
 const fastify = require('fastify')()
 const fs = require('node:fs')
@@ -240,13 +238,13 @@ fastify.post('/upload/files', async function (req, reply) {
 })
 ```
 
-Request body key-value pairs can be assigned directly using `attachFieldsToBody: 'keyValues'`. Field values will be attached directly to the body object. By default, all files are converted to a string using `buffer.toString()` used as the value attached to the body.
+Request body key-value pairs can be assigned directly using `attachFieldsToBody: 'keyValues'`. Field values, including file buffers, will be attached to the body object.
 
 ```js
 fastify.register(require('@fastify/multipart'), { attachFieldsToBody: 'keyValues' })
 
 fastify.post('/upload/files', async function (req, reply) {
-  const uploadValue = req.body.upload // access file as string
+  const uploadValue = req.body.upload // access file as buffer
   const fooValue = req.body.foo       // other fields
 })
 ```