Array

The Array field in allows you to display and manage structured array data. This field supports flexibility in fetching and rendering data, making it suitable for various use cases.

Important

To use the Array field, you must create a resource specifically for it. Refer to the Array Resource documentation for detailed instructions.

For example, to use field :attendees, as: :array, you can generate an array resource by running the following command:

rails generate avo:resource Attendee --array

This step ensures the proper setup of your array field within the Avo framework.

Example 1: Array field with a block

You can define array data directly within a block. This is useful for static or pre-configured data:

class Avo::Resources::Course < Avo::BaseResource
  def fields
    field :attendees, as: :array do
      [
        { id: 1, name: "John Doe", role: "Software Developer", organization: "TechCorp" },
        { id: 2, name: "Jane Smith", role: "Data Scientist", organization: "DataPros" }
      ]
    end
  end
end

Authorization

The array field internally inherits many behaviors from has_many, including authorization. If you are using authorization and the array field is not rendering, it is most likely not authorized.

To explicitly authorize it, define the following method in the resource's policy:

# app/policies/course_policy.rb
class CoursePolicy < ApplicationPolicy
  def view_attendees? = true
end

For more details, refer to the view_{association}? documentation.

Example 2: Array field fetching data from the model's method

If no block is defined, Avo will attempt to fetch data by calling the corresponding method on the model:

class Course < ApplicationRecord
  def attendees
    User.all.first(6) # Example fetching first 6 users
  end
end

Here, the attendees field will use the attendees method from the Course model to render its data dynamically.

Example 3: Fallback to the records method

If neither the block nor the model's method exists, Avo will fall back to the records method defined in the resource used to render the array field. This is useful for providing a default dataset.

When neither a block nor a model's method is defined, Avo will fall back to the records method in the resource used to render the field. This is a handy fallback for providing default datasets:

class Avo::Resources::Attendee < Avo::Resources::ArrayResource
  def records
    [
      { id: 1, name: "Default Attendee", role: "Guest", organization: "DefaultOrg" }
    ]
  end
end

Summary of Data Fetching Hierarchy

When using has_many with array: true, Avo will fetch data in the following order:

1. Use data returned by the block provided in the field.
2. Fetch data from the associated model method (e.g., Course#attendees).
3. Fall back to the records method defined in the resource.

This hierarchy provides maximum flexibility and ensures seamless integration with both dynamic and predefined datasets.