optional local variables in rails partial templates: how do I get out of the (defined? foo) mess?

Question

I\'ve been a bad kid and used the following syntax in my partial templates to set default values for local variables if a value wasn\'t explicitly defined in the :locals has

Answer 1

Since local_assigns is a hash, you could also use fetch with the optional default_value.

local_assigns.fetch :foo, default_value

This will return default_value if foo wasn't set.

WARNING:

Be careful with local_assigns.fetch :foo, default_value when default_value is a method, as it will be called anyway in order to pass its result to fetch.

If your default_value is a method, you can wrap it in a block: local_assigns.fetch(:foo) { default_value } to prevent its call when it's not needed.