The nested rails form assigns a unique identifier to the created field.

Question

I want to assign a unique identifier to each line generated by a nested form.

I examined this question Creating a unique identifier for <fieldset> when using the form_for Rails Nested Model Form , but this does not solve my problem.

Answer 1

In fact, the solution given by Anil Mauria only works for elements that are dynamically added via javascript using the link_to_add provided by the stone. But for me, he would leave new_association for existing elements.

To correctly identify each nested element (even deeply nested), you can use f.index . The advantage is that if the record already exists (that is, if it was in the database), it will simply be replaced by the index that it has in the array. However, using link_to_add will replace f.index identifier automatically generated by nested_form, just like Anil Maurya’s solution.

For deeply nested solutions, instead of just writing fields_for and using the same variable f each time, if you need to label your elements correctly, you must specify which partial to render, and each time use a different f variable that you must convey partial

For example: if you have

 Main has_many :nested1s Nested1 has_many :nested2s Nested2 has_many :nested3s 

Then your code should look like this (I gave an example with tables, because it is more complicated):

 <%= nested_form_for @Main do |main_form| %> <table> <thead> <stuff /> </thead> <%= main_form.fields_for :nested1s, :wrapper => false do |nested1_f| %> <%= render 'main/nested1_fields', nested1_f: nested1_f %> <% end %> 

_nested1_fields.html.erb

 <tbody class="fields"> <tr>Stuff</tr> <tr> <table id="nested1-<%= nested1_f.index %>-nested2s"> <thead>Stuff</thead> <%= nested1_f.fields_for :nested2s, :wrapper => false do |nested2_f| %> <%= render 'main/nested2_fields', nested1_f: nested1_f, nested2_f: nested2_f %> <% end %> </table> </tr> <tr><%= nested1_f.link_to_add 'add nested2', :nested2, :data => { :target => "#nested1-#{nested1_f.index}-nested2s"}, class: "btn btn-sm btn-success" %> </tbody> 

_nested2_fields.html.erb

 <tbody class="fields"> ... <table id="nested1-<%= nested1_f.index %>-nested2-<%= nested2_f.index %>-nested3s"> <%= fields_for :nested3s do |nested3_f| %> ... ... </tbody> 

It is also important to note that gem nested_form will only work well if each nested set of fields is wrapped with a tag with a "field" class

Answer 2

I managed to solve this problem by looking at the socket of a nested form. Inside the embedded gem, a unique identifier is generated dynamically for each addition. the data syntax is parsed, and "new _ # {association}" is replaced by the generated unique identifier. In my case, the relationship was like the "Directories" has_many "Category", so my association was categories. I assigned a new line with id = "new_categories" and replaced it with a unique identifier when a new line was added.

Maybe it is useful to someone else.