ruby on rails - Modify Nested_Field before adding association Cocoon -

after user submits form, before association added, possible modify nested field during time?

for example nested fields may like:

<div class='nested-fields'>    <div class="field">       <%= f.label :count %>       <%= f.number_field :count %>    </div>    <%= link_to_remove_association "remove section", f %> </div> 

say want multiply count x 2 before adding association (after user submits form). possible?

or more complex example, might want convert integer string save association.

link issue: https://github.com/nathanvda/cocoon/issues/361 (i told post on so)

yes, can modify permit params:

def some_params   params.require(:some).permit(:count).tap |white_list|     white_list[:count] = 2 * params[:some][:count].to_i   end end