ruby - How do I check if a Rails.application.config variable is defined? -

even though rails.application.config.trackable_models returns full array, defined?(rails.application.config.trackable_models) returns nil.

rails.application.config.trackable_models # => ["newsitem", "contentpage", "event"] defined?(rails.application.config.trackable_models): # => nil  

setting local variable in same way fine:

foo = ["x"] defined?(foo) # => local-variable 

what proper way check existence of config variable if not "defined?"?

if want check method defined in literal sense, use respond_to

rails.applications.config.respond_to?(:trackable_models) 

if want check if method returns other nil, have options:

tm = rails.applications.config.trackable_models tm.nil? tm.presence || 'default value' tm.present? tm.blank?