{
%w[created_at asc] => :created_at_asc,
%w[created_at desc] => :created_at_desc,
%w[updated_at asc] => :updated_at_asc,
%w[updated_at desc] => :updated_at_desc,
%w[popularity asc] => :popularity_asc,
%w[popularity desc] => :popularity_desc,
%w[milestone_due asc] => :milestone_due_asc,
%w[milestone_due desc] => :milestone_due_desc,
%w[weight asc] => :weight_asc,
%w[weight desc] => :weight_desc,
%w[health_status asc] => :health_status_asc,
%w[health_status desc] => :health_status_desc,
%w[closed_at asc] => :closed_at_asc,
%w[closed_at desc] => :closed_at_desc,
%w[due_date asc] => :due_date_asc,
%w[due_date desc] => :due_date_desc,
[nil, 'created_asc'] => :created_at_asc,
[nil, 'created_desc'] => :created_at_desc,
[nil, 'updated_asc'] => :updated_at_asc,
[nil, 'updated_desc'] => :updated_at_desc,
[nil, 'popularity_asc'] => :popularity_asc,
[nil, 'popularity_desc'] => :popularity_desc,
[nil, 'milestone_due_asc'] => :milestone_due_asc,
[nil, 'milestone_due_desc'] => :milestone_due_desc,
[nil, 'weight_asc'] => :weight_asc,
[nil, 'weight_desc'] => :weight_desc,
[nil, 'health_status_asc'] => :health_status_asc,
[nil, 'health_status_desc'] => :health_status_desc,
[nil, 'closed_at_asc'] => :closed_at_asc,
[nil, 'closed_at_desc'] => :closed_at_desc,
[nil, 'due_date_asc'] => :due_date_asc,
[nil, 'due_date_desc'] => :due_date_desc
}.freeze