How to do an if/else in HAML without repeating indented code
Depending on if a user is signed in or not, I'd like to print a different kind of %body-tag.
This is how I currently do it:
- if defined? @user
%body(data-account="#{@user.account}")
%h1 Welcome
-# all my content
- else
%body
%h1 Welcome
-# all my content
As you can see there's a lot of duplicated code in there. How can I eliminate this? I already tried the following:
- if defined? @user
%body(data-account="#{@user.account}")
- else
%body
%h1 Welcome
-# all my content
Unfortunately, this doesn't work since HAML interprets it as if the %h1 and the content is part of the else-statement, which of course they aren't.
Any ideas on how to solve this? I run in this problem开发者_高级运维 all the time, so I can't imagine there isn't a simple solution for it.
I don't think that you can avoid the indentation issue, because of the way HAML autoassigns the "end" statement, but you can instead push the if statement into the body tag itself -
%body{:data_account => (defined? @user ? @user.account : nil)}
as opposed to
%body(data-account="#{@user.account}")
Not super-pretty, but less ugly than repeating the entire block!
!!!
- @user = "jed" #=> stubbing out an instance
%html
%head
- string = defined?(@user) ? "#{@user}" : nil #=> for demo only, wrap this in a helper method
%title{'data-account' => string}
%body
=yield
HAML's elegant solution is helpers
class ApplicationHelper...
def body_for_user(user, &blk)
return content_tag(:body, :'data-account' => user.account, &blk) if user
content_tag(:body, &blk)
end
end
The ternary operators described above are more than sufficient for this particular situation, but for more complex things, break out the helpers.
Oh, to use this, in your view change %body(...) to = body_for_user @user do
Write a helper like this:
def body_attributes
{}.tap do |hash|
hash[:data] = {}
hash[:data][:account] = @user.account if @user
# add any other attributes for the body tag here
end
end
Then call the helper from the body element:
%body{ body_attributes }
%h1 Welcome
-# all my content
For anybody looking for an answer to the Ruby if/else issue with HAML this is how I worked around it:
%tr{ id: (line_item == @current_item) ? "current_item" : nil }
%td= button_to '-', decrement_line_item_path(line_item), method: :put, remote: true
%td #{line_item.quantity}×
%td= line_item.product.title
%td.item_price= number_to_currency(line_item.total_price)
I usually set the @@menu variable at the controller, then in bootstrap-enabled layout.haml I define:
...
%body
.navbar.navbar-fixed-top
.navbar-inner
.container
%a.btn.btn-navbar{"data-target" => ".nav-collapse", "data-toggle" => "collapse"}
%span.icon-bar
%span.icon-bar
%span.icon-bar
%a.brand{:href => "/"} AwesomeApp
.nav-collapse
%ul.nav
%li{:class => @@menu == 'home' && :active}
%a{:href => "/"} Home
%li{:class => @@menu == 'about' && :active}
%a{:href => "/about"} About
%li{:class => @@menu == 'contact' && :active}
%a{:href => "/contact"} Contact
when I set @@menu to 'about' it will render:
<body>
<div class='navbar navbar-fixed-top'>
<div class='navbar-inner'>
<div class='container'>
<a class='btn btn-navbar' data-target='.nav-collapse' data-toggle='collapse'>
<span class='icon-bar'></span>
<span class='icon-bar'></span>
<span class='icon-bar'></span>
</a>
<a class='brand' href='/'>AwesomeApp</a>
<div class='nav-collapse'>
<ul class='nav'>
<li>
<a href='/'>Home</a>
</li>
<li class='active'>
<a href='/about'>About</a>
</li>
<li>
<a href='/contact'>Contact</a>
</li>
</ul>
</div>
</div>
</div>
</div>
加载中,请稍侯......
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