What's an elegant way to conditionally add a class to an HTML element in a view?

Question

I occasionally have to add a class to an html element based on a condition. The problem is I can\'t figure out a clean way of doing it. Here\'s an example of the stuff I\'ve

Answer 1

I use the first way, but with a slightly more succinct syntax:

Though usually you should represent success with boolean true or a numeric record ID, and failure with boolean false or nil. This way you can just test your variable:

A second form using the ternary ?: operator is useful if you want to choose between two classes:

Finally, you can use Rail's record tag helpers such as div_for, which will automagically set your ID and class based on the record you give it. Given a Person with id 47:

# 

<% div_for @person, class: (@success ? 'good' : 'bad') do %>
<% end %>