change to oneliner: `class flattenarray def self.flatten(ar) [] if ar.nil? ar.flatten.compact end end` in ruby

To change the given code to a single line in Ruby, you can remove the unnecessary line breaks and spaces. Here's the one-liner version of the flattenarray class:

main.rb
class flattenarray; def self.flatten(ar); [] if ar.nil?; ar.flatten.compact; end; end
86 chars
2 lines

This code still defines the flattenarray class with the flatten method, but in a single line format.