Conditional Hash#merge
19 Mar 2022I was in a situation where a key may or may not be present in a Hash (options), and I needed to do two different, but very similar things. The general if/else seemed like too much:
if options[:uniqueness]
if options[:scope]
validates attribute, :uniqueness => { :case_sensitive => true, :scope => options[:scope] }
else
validates attribute, :uniqueness => { :case_sensitive => true }
end
# ...
end
So I found a nice one-liner that cleaned it up!
if options[:uniqueness]
uniqueness_options = {
:case_sensitive => true,
:scope => ( options[:scope] if options.has_key?(:scope))
}.compact
validates attribute, :uniqueness => uniqueness_options
end
Another approach was to use tap (which I need to lookup more about)
{ :a => 'animal' }.tap { |hash|
hash[:b] = 'banana' if true
}
which maybe is better since it supports earlier Ruby version and is still very readable.