wtf_strong_parameters.rb

[1] pry(main)> ActionController::Parameters.new(:a => 1, :b => [1,2,3], :c => nil).permit(:a, :b => [], :c => [])
=> {"a"=>1, "b"=>[1, 2, 3]}

[2] pry(main)> ActionController::Parameters.new(:a => 1, :b => [1,2,3], :c => nil).permit(:a, :c => [], :b => [])
=> {"a"=>1}

[3] pry(main)> ActionController::Parameters.new(:a => 1, :b => [1,2,3], :c => []).permit(:a, :b => [], :c => [])
=> {"a"=>1, "b"=>[1, 2, 3], "c"=>[]}

[4] pry(main)> ActionController::Parameters.new(:a => 1, :b => [1,2,3], :c => []).permit(:a, :c => [], :b => [])
=> {"a"=>1, "c"=>[], "b"=>[1, 2, 3]}