Haml Whitespace Preservation (or: Fixing Textarea Indentation in Haml)

Haml renders HTML with indentation reflecting the nesting level of elements. When it comes to white-space preserving content, this may become a problem: the content will be rendered including the HTML indentation.

Problematic: Preserved Indentation

Copy.nest
  %span Reference
  %pre
    = content

Copy<div class="nest">
    <span>Reference</span>
    <pre>
        Hello
        World
    </pre>
</div>

Better: Without Extra Indentation

Render with tilde ~ instead of equals = to keep Haml from indenting content:

Copy.nest
  %span Reference
  %pre
    ~ content

Copy<div class="nest">
    <span>Reference</span>
    <pre>
Hello
World
    </pre>
</div>

Textareas

In some versions of Haml + Rails, this may also be an issue for textarea elements. Fix it similarly:

Copy# Indented description
= form.text_area :description

# Unindented description
~ form.text_area :description