original content is here : https://bootrails.com/blog/erb-vs-haml/
This is an opinionated article about ERB and HAML with Rails. Let's compare each other and pick a winner.
Use case
In the Ruby-on-Rails world, they are known as templating languages. In the MVC concept, they represent "the View". Both are here to output HTML.
Example
Examples worth a thousand words, so here are two examples, one with ERB, the other with HAML. Both are strictly equivalent. I tried to put different kinds of concepts in order to highlight various problems : create variables, run ruby code, inline style, condition, loop, etc.
ERB template file
<% v = run_some_ruby_code %>
<div id="main" style="margin-left: 0">
<div class="left column">
<h2>Welcome to the library</h2>
<% books.each_with_index do |book, indx| %>
<% if indx > 0 %>
<p><%= book.title %></p>
<% end %>
<% end %>
</div>
<div class="right column">
<%= render "shared/sidebar" %>
</div>
</div>
Is equivalent to this HAML template file :
- v = run_some_ruby_code
#main{style: "margin-left: 0"}
.left.column
%h2 Welcome to the library
- books.each_with_index do |book, indx|
- if indx > 0
%p= book.title
.right.column
= render "shared/sidebar"
ERB
- Plain HTML is still valid, so copy/pasting from other websites is not a problem
- Indent as you like : maybe seen as an advantage : if you'd like to indent it the way you want. Could also be seen as a problem : bad indentation still works...
- Standard with the Rails default stack : that mean more standardisation : better IDE support, legacy app may use it more, and a lowest barrier entry
HAML
- HAML is a lot less verbose - this is the main unfair advantage of HAML.
- HAML must be correctly indented. Sometimes the indentation is not as intuitive as it should. So it's not so cool.
- HAML is also not very intuitive for corner cases (javascript tags, inline CSS...). In this case, you have to use an external online tool.
- Added as a gem, i.e. not included in a default Rails application
- Known as slower than ERB - I didn't notice any practical difference though.
And the winner is
ERB.
I've used both and I have to say HAML has one very big advantage : a lot less verbosity. This is very handy for large template files. But large template files are not so frequent in an application if you properly cut them into small pieces - partial or view_components.
So now HAML's big one advantage doesn't outweigh the sum of its disadvantages : hard to copy/paste from examples, and tricky corner cases notably.
Top comments (1)
Nice! I don't like the mess erb mix leave w/html+ruby. What are the advantages of Haml vs Slim?