instantiation.md

Instantiation

You can, of course, instantiate a store model object using new:

class Configuration
  include StoreModel::Model

  attribute :model, :string
  attribute :color, :string

  validates :color, presence: true
end

config = Configuration.new(model: "spaceship", color: "red")

However, the instance will not have all of the behavior that an instance of a store model "type" would have. For instance, instantiating with new will raise errors when unknown attributes are passed, rather than providing the Unknown attributes behavior.

Store model "types" are what are assigned to attribute definitions in ActiveModel classes.

E.g.:

class Product < ApplicationRecord
  attribute :configuration, Configuration.to_type
end

If you want to instantiate not just a store model class, but the associated type, you can use the from_value class method:

config = Configuration.from_value(model: "spaceship", color: "red", some_other_attribute: "foo")

Similarly, if you want to instantiate an array of store model objects, you can use from_values:

configs = Configuration.from_values([
  {model: "spaceship", color: "red", some_other_attribute: "foo"},
  {model: "car", color: "blue", some_other_attribute: "bar"}
])

These methods are shorthand for

Configuration.to_type.cast_value(value)

and

Configuration.to_array_type.cast_value(values)

respectively.