Don't understand Proxy{Array} in Precognition

[fpolli]

Hi,
I have a form where I use Precognition with Alpine, and on submit, I am trying to iterate the properties of the Precognition form object to create a FormData to submit. Works great except that arrays (multi-select, checkbox group, etc) get added as strings, not arrays. I have done some research on Javascript Proxy objects and I don't really understand them and from what I read, there is no way to get the actual value out of them? But when the validate function submits an array field it submits it as an array.

My form object:

        touchfields: ['work_id', 'genre', 'title', 'tags', 'author_id', 'characters'],
        form: $form('post', '{{route('content.submit', ['mime' => $work?->mime ?? $active['mime']])}}', {
          username: '',
          step: 1,
          work_id: 1,
          genre: 'horror',
          title: 'Scream',
          tags: ['horror','girls','screaming'],
          author_id: 1,
          characters: [1,2,3],
        }),

And in the submit handler:

      let submitData = new FormData()
      for(let key of touchfields) {
        submitData.set(key, form[key])
      }

tags comes out as "horror,girls,screaming" and characters comes out as "1,2,3" instead of as the expected arrays. How can I get them as arrays? Can I? I'd rather not have to explode them on the back end if I don't have to.

Thank you for your time.