Laravel 5.1 and Fractal: including pivot table data on the transformer

Tables: contact, company and a relationship table with a custom pivot attribute company_contact (company_id, contact_id, is_main)

Company and Contact have a many to many relationship (belongsTo on both models).

Expected output when I retrieve the contacts of a company:

{
    "data": [
        {
            "id": 1,
            "name": "JohnDoe",
            "is_main": false
        },
        {
            "id": 2,
            "name": "JaneDoe",
            "is_main": true
        }
    ]
}

Expected output when I retrieve the contact list with ?include=companies:

{
    "data": [
        {
            "id": 1,
            "name": "John Doe",
            "companies": {
                "data": [
                    {
                        "id": 501,
                        "name": "My Company",
                        "is_main": true
                    },
                    {
                        "id": 745,
                        "name": "Another Company",
                        "is_main": false
                    }
                ]
            }
        },
        {
            "id": 2,
            "name": "Jane Doe",
            "companies": {
                "data": [
                    {
                        "id": 999,
                        "name": "Some Company",
                        "is_main": true
                    }
                ]
            }
        }
    ]
}

What's the best way of adding the pivot table attribute? It doesn't seem very clean to add is_main on the company transformer if the attribute is set.

For the first example I was thinking about using parameters ?include=company_relationship:company_id(1) with something like:

public function includeCompanyRelationship(Contact $contact, ParamBag $params) {
    // .. retrieve the pivot table data here
    $is_main = $company->is_main;

    // but now I would need another transformer, when what I actually want is to push the value on the main array (same level)

    return $this->item(??, ??);
}

I understand how to retrieve pivot data (related: Laravel 5.1 - pivot table between three tables, better option?) but not the best way of adding it in the http://ift.tt/1h7EiPY Transformer logic.

I already have a ContactTransformer and CompanyTransformer but if I add is_main to the CompanyTransformer all the calls I make (related or not to contacts) will also expect that attribute.

via Chebli Mohamed