Rails : simple_form : Getting an empty string from checkbox collection

Question

I have the following code in my views

<%= f.input :role_names, as: :check_boxes, collection: @program.role_names %>

And whenever I submit the form I am getting values something like ["admin, "moderator", ""] but I was expecting something like ["admin, "moderator"] , why is this?

Moreover I made a inspect element, and there was a <input name="user[role_names][]" type="hidden" value=""> tag after the last check box, within the same control-group. I suppose this is getting added at the last in the params[:user][:recipient_role_names].

How should I handle this? I know I can do a reject(&:blank?) but is there a cleaner way on params[:user][:recipient_role_names]? I also want to know why the input element is getting added? Is it a bug in simple form or I have done something wrong?

Other info:

1. simple_form gem version: 2.0.4
2. rails version: 3.2.8

Saucier

Answer 1

It's a Rails' feature. You'll be able disable it in Rails 4. You can read more about this on simple form issue #603 and Rails issue #5402

Madura

perfect.. ll accept in 5 mins.. some time constraint.. cant accept now.. Btw I would love to understand why.. do you have any idea why this is a rails feature? I mean why they made this feature? and is this supposed to fix somethings else, if so what was that? It would be great if you could explain about it a little.. thx in advance.. – Saucier

you can read explanation here api.rubyonrails.org/classes/ActionView/Helpers/… (it's Gotcha section) – Madura

Answer 2

Just add include_hidden: false to your input params:

<%= f.input :role_names, 
  as: :check_boxes, 
  collection: @program.role_names, 
  include_hidden: false 
%>

And the empty string value won't be sent in the array.

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Obs: I've just added the simple_form input code here for quick reference, as it was Vasily's answer that pointed me in the right direction. Thank you

Michaels

removing the hidden input makes checkboxes uncheckable, which is not desired – Nightshade