AJAX vote update for a nested resource

rubyonrails-talk
1

I created a house scaffold which has many reviews and the reviews can be voted on. All the reviews for a house are shown on the house show page. Then each review has a vote button and a display to show the current number of votes. I would like the vote button to vanish and the vote count to change by AJAX after each vote.

# reviews/_rev.html.erb <% @house.reviews.each do |review| %> posted <%= time_ago_in_words review.created_at %> ago by <%= review.user.username %> | <p id='votes'><%= pluralize(review.votes_count, 'vote') %></p>

<% if current_user %> <%= form_for(@vote, :remote => true) do |f| %> <%= f.hidden_field "review_id", :value => review.id %> <%= f.hidden_field "user_id", :value => current_user.id %>

<%= f.submit "vote" %> . . .

#votes controller def create

    r = params[:vote][:review_id]     @review = Review.find(r)     @vote = @review.votes.build(params[:vote])     @vote.user_id = current_user.id

    respond_to do |format|       if @vote.save

        format.js { }

#create.js.erb $(document).ready(function(){ alert('voted');

});

$("#votes").html("<%= review.votes_count %>")

As it stands now, the vote will be posted but the AJAX will not work. It will say undefined variable 'review'.

2

You’re defining @review as an instance variable, so you have to use it as one in the view:

$(“#votes”).html(“<%= **@**review.votes_count %>”)

3

That doesn't quite work. When I use <%= @review.votes_count %> in the create.js.erb file it updates the counter on the first review, regardless of whether the vote was placed on the first review or not.

I thought maybe if I loop through the reviews again the create.js.erb file it might work.

<% @house.reviews.each do |review| %> $("#votes").html("<%= review.votes_count %>") <% end %>

This did not work either.

4

That’s to be expected with your HTML.

What you currently have will generate HTML that looks like the following if you have 3 reviews:

1 vote

2 votes

3 votes

$(“#votes”).html(“3 votes”)

$(“#votes”).html(“4 votes”)

$(“#votes”).html(“5 votes”)

See the problem?

The problem is that each paragraph tag has the same ID. jQuery will only update the first one. Each paragraph needs to have a unique ID, then your JavaScript to update the paragraph needs to update the specific unique ID.

Including the primary key in the HTML ID is a good solution:

Then your jQuery can update the specific paragraph that it needs to:

$(“#review_<%= review.id %>”).html(“<%= review.votes_count %>”)

5

I'm not sure why it still isn't working for me.

<p id="review_<%= review.id%>"><%= pluralize(review.votes_count, 'vote') %></p>

create.js.erb $("review_<%= @review.id %>").html("<%= @review.votes_count %>")

I don't see any errors in the log.

6

Solution:

<% @house.reviews.each do |review| %> $("#review_<%= review.id %>").html("<%= pluralize(review.votes_count, 'vote') %>"); <% end %>