libs_code_review_checklist.md

Code Review Checklist

• If needing to filter out records from an ActiveRecord_AssociationRelation object

  • use an ActiveRecord Query Interface method e.g. .where, .joins
  • see Understanding the difference between where and select in Rails

    • The bottom line is that we should always use .where rather than .select to improve the speed and save the memory of the application.

  e.g.

  # bad
  # Co Pilot example
  removal_child.children_groups.select { |child| child.id != removal_child.id }
  
  # my example
  removal_child.children_groups.filter { |child_group| child_group.group.present? }
  
  #good
  # Co Pilot example
  removal_child.children_groups.where.not(id: removal_child.id)
  
  # my example
  removal_child.children_groups.joins(:group)
       .where.not(group_id: existing_child.children_groups.map(&:group_id))

If needing to filter out records from an ActiveRecord_AssociationRelation object, use where instead of select to avoid loading the records into memory.

From chat with Mat:

• levels of understanding
• some cases it is better to load everything in memory, and then use select
• need to have data there for mutiple reasons e.g.
  • current user in system
  • load all relations and then do select to find admin relations children
  • media in stories or com posts - media items, select, documents! on com posts