Performance-CollectionLiteralInLoop.md

Pattern: Use of collection literal in loop

Issue: -

Description

This rule identifies places where Array and Hash literals are used within loops. It is better to extract them into a local variable or constant to avoid unnecessary allocations on each iteration.

You can set the minimum number of elements to consider an offense with MinSize.

Examples

# bad
users.select do |user|
  %i[superadmin admin].include?(user.role)
end

# good
admin_roles = %i[superadmin admin]
users.select do |user|
  admin_roles.include?(user.role)
end

# good
ADMIN_ROLES = %i[superadmin admin]
...
users.select do |user|
  ADMIN_ROLES.include?(user.role)
end

Further Reading

• RuboCop - Performance/CollectionLiteralInLoop