I have this form
<%= form_for @lesson do |f| %>
<%= f.label :lesson_name, "Lesson title" %></br>
<%= f.text_field :lesson_name, class: "form-control" %></br>
<%= f.label :lesson_icon, "Choise icon" %>
<%= f.select "lesson_icon", options_for_select([ "ico-03",
"ico-04","ico-05","ico-06" ])%></br></br>
<div>
<p style="display:none"><%=hh=0%></p>
<%= f.fields_for :sublessons do |sublesson_a| %>
<div class="delete-subtitle-<%=hh%>" style="padding-bottom:
25px;">
<%= sublesson_a.label :sublesson_name, "Subtitle 1"
%></br>
<%= sublesson_a.text_field :sublesson_name, class:
"form-control delete-sublesson-field-#{hh}" %></br>
<%= sublesson_a.label :sublesson_content, "Content"
%></br>
<%=sublesson_a.text_area 'sublesson_content', rows: 3,
class: "form-control delete-sublesson-content-#{hh}"%></br>
<%= sublesson_a.label :sublesson_video_link, "Video link"
%><br>
<%= sublesson_a.text_field :sublesson_video_link, class:
"form-control delete-sublesson-video-#{hh}" %></br>
<a style="float:right" class="btn btn-primary"
id="remove_sublesson" onclick="remove_sublesson(<%=hh%>)">Delete
Sublesson</a>
<p style="display:none"><%= hh=hh+1%></p>
</div>
<%end%>
</div>
<%= f.submit "Submit", class: "btn btn-primary" %>
<a class="btn btn-primary" id="addNewTag"
onclick="add_sublesson()">Add Sublesson</a>
<% end %>
This is a form for edit....How can i test if :sublessons is empty?