Use custom content type as field in another custom content type field in drupal 8

Question

Our use case if to have composition of one content type as array in another custom content type. We are trying to represent the following structure in Drupal.

{
        columns: 2,
        theme: 'red',
        sections: [
          {
            title: 'Title 1',
            description: 'Description 1',
            linkLabel: 'Link Label',
            linkUri: 'http://www.some-link.com',
          },
          {
            title: 'Title 2',
            description: 'Description 2',
            linkLabel: 'Link Label',
            linkUri: 'http://www.some-link.com',
          },
        ],
      },

For this one, We have created a custom content type in the Drupal, which holds first-level data, which is columns and theme. For sections, we have created another content type and we want to have that as composition in the parent structure similar to basic data type in drupal which is List(text).

We have 2 questions:

1. Are we in the correct direction?
2. If yes, then is it possible to achieve this via composition? Is there any extension for this one?

Answer 1

The first thing that comes to mind is a field of type "Reference" on the first content type that allows you to reference multiple entities of the second type. That should be possible without custom code.

So yes, I think it can be done that way, and the feature you are looking for may be the Reference type (also known as "entity reference") which is built in.

The columns counter looks a bit redundant if that number is just the number of items in the sections field.

If the contents of the second type (the sections) are not really independent entities you may also consider implementing them as a custom field type that can have arbitrary properties.