Jensseger BelongsToMany returns nothing when selecting fields

Question

I'm working with a Mongo database, and i have a Reading List with a BelongsToMany Relationship to a Stories table, it seems like this:

public function stories()
{
    return $this->belongsToMany(Story::class, null);
}

Then, on the controller, i want to return a list of them, which contains only the id and title of the story list, i searched, and found many ways, but all them caused the same error, this is one of them:

$user = auth()->user();

$readingList = ReadingList::where('user_id', $user->id)->with(["stories"=> function ($query) {

    $query->select("title");

}])->paginate(10);

And causes: Invalid argument supplied for foreach().

I took out the filter to verify it works, and answered correctly.

[
    {
        "_id": "6148dc2a23ef6d0e6838h123",
        "name": "MyReadingList",
        "stories": [
            {
                "_id": "611a64f5f735f32dcc5ab657",
                "title": "Lorem",
                "blurb": "Ipsum"
            }
        ]
    }
]

Am i doing this wrong, or how do you filter the fields with Jensseger library and BelongsToMany?

UPDATE

After a little debugging, seems like i found the cause, but i'm not sure how to solve it, in the Jensseger BelongsToMany file, there is a function like this:

protected function buildDictionary(Collection $results)
{
    $foreign = $this->foreignPivotKey;

    // First we will build a dictionary of child models keyed by the foreign key
    // of the relation so that we will easily and quickly match them to their
    // parents without having a possibly slow inner loops for every models.
    $dictionary = [];

    foreach ($results as $result) {
        foreach ($result->$foreign as $item) {
            $dictionary[$item][] = $result;
        }
    }

    return $dictionary;
}

Here, $result is equal to {"_id":"6148dc2a23ef6d0e6838h123"}, which is my filtered result, but then it tries to access $result->$foreign, where $foreign is 'reading_list_ids', the pivot column, but is not here, hence returning a null and launching that error.

I tried adding reading_list_ids(And removing it from hidden) like $readingList = ReadingList::where('user_id', $user->id)->with("stories:title,reading_list_ids")->get();, still didn't work. Interestingly, i tried testing this without the filter, but with reading_list_ids hidden, it showed something like this {"_id":"6148dc2a23ef6d0e6838h123","title":"Lorem","blurb":"Ipsum","completed":"1"}, still not that field there, but it doesn't launch that error and works.

Does anyone knows how to bypass this, or make it work?

Jensseger BelongsToMany returns nothing when selecting fields

0 Answers0