form-data-parser needs a code example to take another parameter

[kenn]

parseFormData takes uploadHandler at the second arg, but since the function only takes one arg which is (fileUpload: FileUpload), it's hard to make it reusable.

To pull it outside of action, we have to do a higher order function gymnastics like this:

async function uploadHandler(id: string) {
  return async (fileUpload: FileUpload) => {
    if (
      fileUpload.fieldName === 'file' &&
      fileUpload.type.startsWith('image/')
    ) {
      let storageKey = `upload-${id}`
      await fileStorage.set(storageKey, fileUpload)
      return fileStorage.get(storageKey) // => LazyFile
    }
  }
}

export async function action({ request, params }) {
  let formData = await parseFormData(request, await uploadHandler(params.id))
  // ...
}

This is fine, but I think it's unkind to less experienced users.

Until we figure out a better API, can we at least put this example in a visible place? The current README has a bug with referencing user.id.

If I should create a PR for this, let me know.

Thanks for this great library!

[kenn]

Also, it's not clear to me how I can return an extra value from uploadHandler.

For instance, I'm creating a DB record that keeps uploaded file's metadata, and would like to return upload.id which is only generated and accessible inside the handler function.

Also it can even receive multiple files in one request, which makes things even more complicated...

What is a suggested solution here?

export async function uploadHandler(id: string) {
  return async (fileUpload: FileUpload) => {
    let upload = await Upload.create({
      owner_id: id,
      name: fileUpload.name,
    })
    let storageKey = `image-${upload.id}`
    await FileStorage.set(storageKey, fileUpload)
    return FileStorage.get(storageKey)
  }
}

export async function action({ request, params }) {
  let formData = await parseFormData(request, await uploadHandler(params.id))
  // how can I access upload.id(s) just generated?
}