Rails 6.1 added delegated_type which resembles polymorphic relations.
Using delegated_type the developer is introduced with a bunch of useful methods and scopes.
Checkout this
PR
to know more about this feature.
Before
For the sake of understanding,
let’s consider the following declaration of the Note model.
# app/models/notes.rb
class Note < ApplicationRecord
delegated_type :authorable, types: %w[ Customer Employee ]
end
# app/models/employee.rb
class Employee < ApplicationRecord
endPreviously,
in order to create a new delegated_type record,
we would do something like this:
emp_one = Employee.create!(name: "emp one")
Note.create!(authorable: emp_one, body: "sample text")If we try to save the note using nested attributes, it will raise an error:
params = { note: { authorable_type: 'Employee', body: "sample text", authorable_attributes: { name: 'Emp one' } } }
Note.create!(params[:note])
# ArgumentError: Cannot build association `authorable'. Are you trying to build a polymorphic one-to-one association?After
With Rails 7 adding support of accepts_nested_attributes_for for delegated_type
we can save the records as follows:
# app/models/notes.rb
class Note < ApplicationRecord
delegated_type :authorable, types: %w[ Customer Employee ]
accepts_nested_attributes_for :authorable
endparams = { note: { authorable_type: 'Employee', body: "sample text", authorable_attributes: { name: 'Emp one' } } }
note = Note.create!(params[:note])To know more about this feature, checkout this PR.
