Eloquent Api Resource: show one column from pivot table - laravel

Question

I have a vehicle database with a many to many relation with my variant and country table. I only want to show the title that's in my pivot (countries_variants) table. But when I set the relation in my api resource file, it shows all the columns from variants, countries_variants and countries table. Is there a way to only get the title from the pivot table?
Here is my Variant Model:
public function countries(): BelongsToMany
{
return $this->belongsToMany(Country::class, 'countries_variants')->withPivot('title');
}
VariantResource.php
public function toArray($request)
{
return [
'title' => $this->countries->first->title,
];
}
VariantController.php
public function index()
{
return new VariantCollection(Variant::paginate(50));
}
The output I'm getting is:
{
"data": [
{
"title": {
"id": 1,
"title": "Nederland",
"country_code": "NL",
"language_code": "NL_nl",
"pivot": {
"variant_id": 1,
"country_id": 1,
"title": "3/5 deurs"
}
}
}
]
}
I just want to show "title": "3/5 deurs" and not the other data.
I thought that if I set withPivot('title') in my model, it will only show that title and not the foreign keys (variant_id and country_id). Apparently thought wrong..
I tried adding this as well:
'variant_title' => $this->whenPivotLoaded('countries_variants', function () {
return $this->pivot->title;
}),
But the data then returns empty.
Any help would be very much appreciated :)

Answer 1

Try changing
$this->countries->first->title
To
$this->countries->first->title->pivot->title
When you do withPivot('title') you are telling Eloquent to also get title column, if you do not do that, you will only get the keys (variant_id and country_id in your case).
More info here.

Answer 2

Okay so I finally figured it out. I looked through the official laravel docs again and I found this.
So I changed my CountryVariant model class to extend Pivot instead of Model.
Like so:
use Illuminate\Database\Eloquent\Relations\Pivot;
class CountryVariant extends Pivot {
public function variant(): BelongsTo
{
return $this->belongsTo(Variant::class);
}
}
Now in my VariantResource.php I added this:
public function toArray($request): array
{
$items = [];
foreach ($this->countries()->get() as $country) {
$items[$country->language_code] = $country->pivot->only('title');
}
return $items;
}
I also changed the pivot table names to be singular like: country_variant (I had it plural).
Apparently the problem was that in my model it was looking for a primary key which I didn't have in my pivot table. I only had foreign keys and an additional column: 'title'. It took one of my foreign keys and used it as a primary one. So when I extended with extends pivot it would ignore the primary key and I could collect my alternate column 'title' by using country->pivot->only('title') in my resource file.
I hope this helps some one else.