Question

I am trying to get my form to submit and display results without refreshing the page using Ajax. Problem is that it does not seem that the methods are getting returned, they are all coming up undefined once submitted.

_micropost.html.erb

  <li>
  <span class="content"><%= micropost.content %></span>
  <span class="timestamp">
    Posted <%= time_ago_in_words(micropost.created_at) %> ago.
  </span>
  <% if current_user?(micropost.user) %>
    <%= link_to "delete", micropost, method: :delete,
                                     data: { confirm: 'You sure?' },
                                     title: micropost.content %>
  <% end %>
</li>

create.js.erb

$(".microposts").append("<%= escape_javascript(render('shared/feed')) %>")

microposts_controller.rb

class MicropostsController < ApplicationController

  before_filter :authenticate
  before_filter :authroized_user, :only => :destroy
  def create
    @micropost = current_user.microposts.build(params[:micropost])
    if @micropost.save!
      respond_to do |format|
        format.html { redirect_to @user }
        format.js
      end
  end
end

  def destroy
    @micropost.destroy
    redirect_to root_path, :flash => { :success => "Micropost deleted!" }
  end

  private
  def authroized_user
    @micropost = Micropost.find(params[:id])
    redirect_to root_path unless !current_user?(@micropost.user)    
  end

end

_feed.html.erb

<% if @feed_items.any? %>
  <ol class="microposts">
    <%= render partial: 'shared/feed_item', collection: @feed_items %>
  </ol>
  <%= will_paginate @feed_items %>
<% end %>

_feed_item.html.erb

<li id="<%= feed_item.id %>">
  <%= link_to gravatar_for(feed_item.user), feed_item.user %>
  <span class="user">
    <%= link_to feed_item.user.name, feed_item.user %>
  </span>
  <span class="content"><%= feed_item.content %></span>
  <span class="timestamp">
    Posted <%= time_ago_in_words(feed_item.created_at) %> ago.
  </span>
  <% if !current_user?(feed_item.user) %>
    <%= link_to "delete", feed_item, method: :delete,
                                     data: { confirm: "You sure?" },
                                     title: feed_item.content %>
  <% end %>
</li>

error log on post

    Started POST "/microposts" for 127.0.0.1 at 2012-11-24 10:20:26 -0800
Processing by MicropostsController#create as JS
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"+x5dhM0t5pZzB0flEo46n+Rr8OKcxNdgaAgvkh46dek=", "micropost"=>{"content"=>"Please work"}, "commit"=>"Post"}
  User Load (0.4ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 103 LIMIT 1
  CACHE (0.0ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 103 LIMIT 1
   (0.1ms)  BEGIN
  SQL (0.6ms)  INSERT INTO "microposts" ("content", "created_at", "updated_at", "user_id") VALUES ($1, $2, $3, $4) RETURNING "id"  [["content", "Please work"], ["created_at", Sat, 24 Nov 2012 18:20:26 UTC +00:00], ["updated_at", Sat, 24 Nov 2012 18:20:26 UTC +00:00], ["user_id", 103]]
   (1.7ms)  COMMIT
  Rendered shared/_feed.html.erb (2.2ms)
  Rendered microposts/create.js.erb (4.1ms)
Completed 500 Internal Server Error in 14ms

ActionView::Template::Error (undefined method `any?' for nil:NilClass):
    1: <% if @feed_items.any? %>
    2:   <ol class="microposts">
    3:     <%= render partial: 'shared/feed_item', collection: @feed_items %>
    4:   </ol>
  app/views/shared/_feed.html.erb:1:in `_app_views_shared__feed_html_erb___3604038303202035148_70347748984380'
  app/views/microposts/create.js.erb:1:in `_app_views_microposts_create_js_erb__2642480281700969603_70347793753860'
  app/controllers/microposts_controller.rb:8:in `create'


  Rendered /usr/local/rvm/gems/ruby-1.9.3-p286/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/_trace.erb (2.0ms)
  Rendered /usr/local/rvm/gems/ruby-1.9.3-p286/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (1.4ms)
  Rendered /usr/local/rvm/gems/ruby-1.9.3-p286/gems/actionpack-3.2.8/lib/action_dispatch/middleware/templates/rescues/template_error.erb within rescues/layout (11.6ms)

linkto github
https://github.com/thebusiness11/appsample

error rendering microposts/micropost partial

Started POST "/microposts" for 127.0.0.1 at 2012-11-24 12:23:25 -0800
Processing by MicropostsController#create as JS
  Parameters: {"utf8"=>"✓", "authenticity_token"=>"+x5dhM0t5pZzB0flEo46n+Rr8OKcxNdgaAgvkh46dek=", "micropost"=>{"content"=>"rendering microposts/micropost partial\r\n"}, "commit"=>"Post"}
  User Load (0.7ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 103 LIMIT 1
  CACHE (0.0ms)  SELECT "users".* FROM "users" WHERE "users"."id" = 103 LIMIT 1
   (0.2ms)  BEGIN
  SQL (5.5ms)  INSERT INTO "microposts" ("content", "created_at", "updated_at", "user_id") VALUES ($1, $2, $3, $4) RETURNING "id"  [["content", "rendering microposts/micropost partial\r\n"], ["created_at", Sat, 24 Nov 2012 20:23:25 UTC +00:00], ["updated_at", Sat, 24 Nov 2012 20:23:25 UTC +00:00], ["user_id", 103]]
   (2.2ms)  COMMIT
  Rendered microposts/_micropost.html.erb (26.8ms)
  Rendered microposts/create.js.erb (32.4ms)
Completed 500 Internal Server Error in 140ms

ActionView::Template::Error (undefined method `content' for nil:NilClass):
    1: <li>
    2:   <span class="content"><%= micropost.content %></span>
    3:   <span class="timestamp">
    4:     Posted <%= time_ago_in_words(micropost.created_at) %> ago.
    5:   </span>
  app/views/microposts/_micropost.html.erb:2:in `_app_views_microposts__micropost_html_erb__2883653912254136485_70298849712020'
  app/views/microposts/create.js.erb:1:in `_app_views_microposts_create_js_erb__910732530435705121_70298849590600'
  app/controllers/microposts_controller.rb:8:in `create'

Answer 1

So it turns out all I needed to do was pass the object @micropost

$(".microposts").prepend("<%= escape_javascript(render(:partial => 'shared/feed_item', :object => @micropost)) %>")