Laravel Nova: Partition to display other table's column - laravel

Question

I'm using Laravel Nova partition to show an amount of items per category.
public function calculate(Request $request) {
return $this->count($request, Item::class, 'category_id');
}
This works fine, but displays on the screen the category_id of course.
I would rather want to show the category_name.
The model is built as follows:
class Item extends Model
{
public function category()
{
return $this->belongsTo('App\Category');
}
}
and
class Category extends Model
{
public function item()
{
return $this->hasMany('App\Item');
}
}
Also, I have in the Nova Category resource defined the following:
public static $title = 'category_name';
How can I show the category name instead of the category id?

Answer 1

From the documentation
Often, the column values that divide your partition metrics into
groups will be simple keys, and not something that is "human
friendly". Or, if you are displaying a partition metric grouped by a
column that is a boolean, Nova will display your group labels as "0"
and "1". For this reason, Nova allows you to provide a Closure that
formats the label into something more readable:
/**
* Calculate the value of the metric.
*
* #param \Illuminate\Http\Request $request
* #return mixed
*/
public function calculate(Request $request)
{
return $this->count($request, User::class, 'stripe_plan')
->label(function ($value) {
switch ($value) {
case null:
return 'None';
default:
return ucfirst($value);
}
});
}
So, in your case, it would be something like this:
/**
* Calculate the value of the metric.
*
* #param \Illuminate\Http\Request $request
* #return mixed
*/
public function calculate(Request $request)
{
return $this->count($request, Item::class, 'category_id');
->label(function ($value) {
// Get your category name here
// For example: return \App\Category::find($value)->name;
});
}