Eager Load Depending on Type of Association in Ruby on Rails

Question

I have a polymorphic association (belongs_to :resource, polymorphic: true) where resource can be a variety of different models. To simplify the questio

Answer 1

I've come up with a viable solution for myself when I was stuck in this problem. What I followed was to iterate through each type of implementations and concatenate it into an array.

To start with it, we will first note down what attributes will be loaded for a particular type.

ATTRIBS = {
  'Order' => [:address],
  'Customer' => [:location]
}.freeze

AVAILABLE_TYPES = %w(Order Customer).freeze

The above lists out the associations to load eagerly for the available implementation types.

Now in our code, we will simply iterate through AVAILABLE_TYPES and then load the required associations.

issues = []

AVAILABLE_TYPES.each do |type|
  issues += @issues.where(resource_type: type).includes(resource: ATTRIBS[type])
end

Through this, we have a managed way to preload the associations based on the type. If you've another type, just add it to the AVAILABLE_TYPES, and the attributes to ATTRIBS, and you'll be done.