Order By Before Where (ARCH6076)

Key ruby.performance.orderby-before-where · Severity warning · Category performance

Sorting before filtering in a collection chain sorts a larger set than needed. Filter first, then sort.

Incorrect

def top_active(users)
  users.sort_by(&:created_at)
       .select(&:active?)
       .first(10)
end

Correct

def top_active(users)
  users.select(&:active?)
       .sort_by(&:created_at)
       .first(10)
end

Fix

Apply the filter before the sort in the chain so a smaller set is sorted.