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PORails 3 nested model form creates duplicate model objects
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  1. PORails 3 nested model form creates duplicate model objects
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    copied!<p>I've followed along with Ryan Bates' tutorial (<a href="http://railscasts.com/episodes/196-nested-model-form-revised" rel="nofollow">Episode 196 - Nested Model Forms (Revised)</a>) to create a form for a model (<code>Employee</code>) with a nested <code>has_many :through</code> model (<code>Capability</code>). For the most part it works; however, when I click the link to add a new model object to the form, <em>two</em> are created and inserted. I don't know why - I've struggled with this for a few evenings now and just can't work it out. Can anyone point out where I've gone wrong?</p> <p>(<code>Capability</code> here represents a <code>has_many through</code> association: <code>Employee has_many :roles, through: :capabilities</code>).</p> <h3>form partial</h3> <pre><code>&lt;%= form_for(@employee) do |f| %&gt; # Employee fields here ... &lt;%= f.fields_for :capabilities do |builder| %&gt; &lt;%= render 'capability_fields', f: builder %&gt; &lt;% end %&gt; &lt;%= link_to_add_fields "Add capability", f, :capabilities %&gt; &lt;%= f.submit "Submit", :class =&gt; 'submit' %&gt; &lt;% end %&gt; </code></pre> <h3>capability_fields partial</h3> <pre><code>&lt;fieldset&gt; &lt;%= f.select :role_id, Role.all.collect{ |r| [r.name, r.id]} %&gt; &lt;%= f.check_box :primary_role_flag %&gt; &lt;%= f.text_field( :valid_from, :class =&gt; 'date') %&gt; &lt;%= f.text_field( :expires_on, :class =&gt; 'date') %&gt; &lt;%= f.hidden_field :_destroy %&gt; &lt;%= link_to "Remove", '#', class: "remove_fields" %&gt; &lt;/fieldset&gt; </code></pre> <h3>link_to_add_fields application helper</h3> <pre><code>def link_to_add_fields(name, f, association) new_object = f.object.send(association).klass.new id = new_object.object_id fields = f.fields_for(association, new_object, child_index: id) do |builder| render(association.to_s.singularize + "_fields", f: builder) end link_to(name, '#', class: "add_fields", data: {id: id, fields: fields.gsub('\n','&amp;#xA')}) end </code></pre> <h3>jQuery coffeescript</h3> <pre><code>jQuery -&gt; $('form').on 'click', '.remove_fields', (event) -&gt; $(this).prev('input[type=hidden]').val('1') $(this).closest('fieldset').hide() event.preventDefault() $('form').on 'click', '.add_fields', (event) -&gt; time = new Date().getTime() regexp = new RegExp($(this).data('id'), 'g') $(this).before($(this).data('fields').replace(regexp, time)) event.preventDefault() </code></pre>
 

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