Rails form_for added empty model

Question

I have started the "Get Started Guide" from the ruby on rails website. Everything works fine, but when I change the order of showing all comments and than display the comments-form in the other way round, than the form_forfunction adds a empty comments model to @post.comments and so, I display one empty comment in the loop. Here is the view:

<h1><%= @post.name %></h1>
<p><%= @post.text %></p>
<h2>Add comment</h2>
<%= form_for([@post, @post.comments.build]) do |f| %>
  <p>
    <%= f.label :name %><br>
    <%= f.text_field :name %>
  </p>
  <p>
    <%= f.label :email %><br>
    <%= f.text_field :email %>
  </p>
  <p>
    <%= f.label :text %><br>
    <%= f.text_area :text %>
  </p>
  <p>
    <%= f.submit %>
  </p>
<% end %>
<h2>Comments</h2>
<%= render @post.comments %>

The loop display two comments. One, that exists in the db and one, that has just empty attributes. If I delete the form, than all is shown up correct.

You should also display your posts controller.

MarsAtomic
– MarsAtomic

2015-07-12 17:31:01 +00:00
Commented Jul 12, 2015 at 17:31 — MarsAtomic
– MarsAtomic, Commented Jul 12, 2015 at 17:31

Marius Pop · Accepted Answer · 2015-07-12 18:54:51Z

1

You can select only your persisted comments:

<%= render @post.comments.select(&:persisted?) %>

answered Jul 12, 2015 at 18:54

Marius Pop

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Comments

Athar · Accepted Answer · 2015-07-12 19:01:51Z

1

When you do post.comments.build against some post, it will be added to the post.comments collection and will be displayed along with other comments.

You can always use persisted to check if the object is present in database meaning id is assigned to it.

 @post.comments.select(&:persisted?)

Note: .present? check donot work here so you have to use .persisted.? present check only assosiated to the parent.

answered Jul 12, 2015 at 19:01

Athar

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