Rails - Strong parameters with empty arrays

Question

I\'m sending an array of association ids, say foo_ids to my controller. To permit an array of values, I use:

params.permit(foo_ids: [])

Answer 1

I ran into the same issue and found a similar solution as Donato, albeit while constructing a multipart FormData in JS. The trick was to put an empty string in the array.

const formData = new FormData()
formData.append('dish[tag_ids][]', '')

On the controller side, params arrives with "dish"=>{"tag_ids"=>[""]}, which dish.update interprets as "remove all tags".