Add as favorite with no full page refresh - ruby-on-rails

Question

I am working on a Hiragana flashcards app.
I spend nights and days to understand how don't refresh full page when I add a flashcard (hiragana) as a favorite.
Here is the favorite controller
class FavsController < ApplicationController
def index
#favs = Fav.where(user: current_user)
end
def create
#hiragana = Hiragana.find(params[:hiragana_id])
#fav = current_user.favs.new(hiragana: #hiragana)
if not #hiragana.favs.where(user: current_user).take
#fav.save
end
render json: #fav
end
def destroy
#fav = Fav.find(params[:id])
#fav.destroy
redirect_to :back
end
end
I render json in the create method and when I click on view I add only an hash
render view favorite
<% if current_user %>
<div class="hiragana-fav">
<% if hiragana.is_faved_by(current_user) %>
<%= link_to fav_path(hiragana.is_faved_by(current_user)), method: :delete do %>
<i class="fa fa-heart faved faved-on"></i>
<% end %>
<% else %>
<%= link_to hiragana_favs_path(hiragana), method: :post do %>
<i class="fa fa-heart faved faved-off"></i>
<% end %>
<% end %>
</div>
<% end %>
and it is located in hiragana render
<div class="row">
<ul class="list-inline text-center card-frame">
<li>
<div class="card">
<div class="front">
<% if current_user.try(:admin?) %>
<%= link_to hiragana_path(hiragana), class:'trash-hiragana', data: { confirm: 'Are you sure?' }, method: :delete do %>
<%= image_tag("delete-btn.png") %>
<% end %>
<% end %>
<span class="card-question img-popover" data-content="<h4 class='text-center letter-uppercase'><%= hiragana.bigletter.upcase %></h4><p class='text-center'><b><%= hiragana.midletter %></b> comme dans <b><%= hiragana.transcription %></b></p>">
<i class="fa fa-eye fa-lg"></i>
</span>
<div class="card-hiragana hiragana-<%=hiragana.bigletter.downcase.last%>">
<h1><b><%= hiragana.ideo1 %></b></h1>
</div>
<div class="card-katakana">
<p><%= hiragana.ideo2 %></p>
</div>
<%= render 'favs/favorites', hiragana: hiragana %>
</div>
<div class="back">
<div class="col-sm-3 col-xs-4 col-md-3 containerbackcards-<%=hiragana.bigletter.downcase.last%>">
<div class="backcard-hiragana">
<h1><b><%= hiragana.ideo1 %></b></h1>
</div>
<div class="card-bigletter">
<h4><%= hiragana.bigletter.upcase %></h4>
</div>
</div>
</div>
</div>
</li>
</ul>
</div>
When I add a card as favorite it gives me a hash like this :
{
id: 64,
user_id: 1,
hiragana_id: 4,
created_at: "2016-02-10T16:37:26.270Z",
updated_at: "2016-02-10T16:37:26.270Z"
}
I just want to have the heart grey to red as favorite, saved and not refresh the entire page. Your explainations are appreciated thank you.

Answer 1

In order to send the request to the controller without the page refreshing you need to use a combination of Ajax and JavaScript.
You use JavaScript to add a click listener to the .faved-on button and to trigger the Ajax request. You will also use JavaScript to prevent the default action occurring when you click the link ie. The Page Refresh
You then use Ajax to send the request to the controller and handle the response.
Your initial JavaScript code looks pretty correct, except you are missing the bit to stop the page from reloading.
See the e.preventDefault(); line below
$(document).ready(function() {
$('.faved-on').click(function(e) { //make sure to pass in the e (the event paramter)
e.preventDefault(); //this is the line you are missing
var fav = $('.faved-off')
//let your ajax handle the rest then
$.ajax({
type: "POST", url: "/hiraganas", dataType: "json",
success: function(data) {
console.log(data);
//change the color of your heart to red here
},
error: function(jqXHR) {
console.error(jqXHR.responseText);
}
});
})
})
I haven't tested your JavaScript but it looks pretty close to correct, I believe its the e.preventDefault(); bit you were missing