Laravel retrieving eloquent nested eager loading - php

Question

In my application i have 4 models that relate to each other.
Forms->categories->fields->triggers
What I am trying to do is get the Triggers that refer to the current Form.
Upon researching i found nested eager loading, which would require my code to look like this
Form::with('categories.fields.triggers')->get();
Looking through the response of this i can clearly see the relations all the way down to my desired triggers.
Now the part I'm struggling with is only getting the triggers, without looping through each model.
The code i know works:
$form = Form::findOrFail($id);
$categories = $form->categories;
foreach ($categories as $category) {
$fields = $category->fields;
foreach ($fields as $field) {
$triggers[] = $field->triggers;
}
}
I know this works, but can it be simplified? Is it possible to write:
$form = Form::with('categories.fields.triggers')->get()
$triggers = $form->categories->fields->triggers;
To get the triggers related? Doing this as of right now results in:
Undefined property: Illuminate\Database\Eloquent\Collection::$categories
Since it is trying to run the $form->categories on a collection.
How would i go about doing this? Do i need to use the HasManyThrough relation on my models?
My models
class Form extends Model
{
public function categories()
{
return $this->hasMany('App\Category');
}
}
class Category extends Model
{
public function form()
{
return $this->belongsTo('App\Form');
}
public function fields()
{
return $this->hasMany('App\Field');
}
}
class Field extends Model
{
public function category()
{
return $this->belongsTo('App\Category');
}
public function triggers()
{
return $this->belongsToMany('App\Trigger');
}
}
class Trigger extends Model
{
public function fields()
{
return $this->belongsToMany('App\Field');
}
}
The triggers run through a pivot table, but should be reachable with the same method?

Answer 1

I created a HasManyThrough relationship with unlimited levels and support for BelongsToMany:
Repository on GitHub
After the installation, you can use it like this:
class Form extends Model {
use \Staudenmeir\EloquentHasManyDeep\HasRelationships;
public function triggers() {
return $this->hasManyDeep(Trigger::class, [Category::class, Field::class, 'field_trigger']);
}
}
Form::with('triggers')->get();
Form::findOrFail($id)->triggers;