Why many people use “-%>” instead of “%>” in Rails? [duplicate]

Question

This question already has an answer here:

• What is the difference between <%, <%=, <%# and -%> in ERB in Rails? 7 answers

Sorry for this question, i think its more offtopic, but i couldn't find anything on google!

I saw now multiple times that a lot of people use -%> instead of just %>. Whats the sense?

Example:

<% @images.each_slice(6) do |slice| -%>
  <div class="gallery">
    <% slice.each do |image| -%>
      <%= image_tag(image.url, :alt => image.alt) %>
    <% end -%>
  </div>
<% end -%>

Source: Rails each loop insert tag every 6 items?

Here he has also used -%> for all blocks.

Answer 1

I would like to add some resources that I know about ERB :

• Rails extends ERB, so that you can suppress the newline simply by adding a trailing hyphen to tags in Rails templates:

  <ul>
    <% for @item in @items -%>
      <li><%= @item %></li>
    <% end -%>
  </ul>
  

• Comment markers use a hash sign:

   <%# This is just a comment %>
  

• A tag with an equals sign indicates that enclosed code is an expression, and that the renderer should substitute the code element with the result of the code (as a string) when it renders the template. Use an expression to embed a line of code into the template, or to display the contents of a variable:

   Hello, <%= @name %>.
   Today is <%= Time.now.strftime('%A') %>.
  

• With one equal sign the string will be encoded. To avoid encoding, you can use two equals signs (or raw):

      Hello, <%== @unencodedOutput %>
  

• Tags without the equals sign denote that the enclosed code is a scriptlet. Each scriptlet is caught and executed, and the final result of the code is then injected in to the output at the point of the scriptlet.

  <ul>
    <% for @item in @shopping_list %>
      <li><%= @item %></li>
    <% end %>
  </ul>
  

  Scriptlets are most commonly used for embedding loops or conditional logic into templates:

Read An Introduction to ERB Templating to know more.