tojson() does not return all related models - laravel

Question

I am working on laravel 5.5 project
i have four tables as following:-
1- Subject model (has following relations)
public function types()
{
return $this->belongsToMany('App\Types');
}
public function areas()
{
return $this->belongsToMany('App\Area');
}
public function articles()
{
return $this->hasMany('App\Article');
}
2- Area and Types has many to many relation with Subject model
public function subjects()
{
return $this->belongsToMany('App\Subjects');
}
3- Article has 1 to many relation with Subject
public function subjects()
{
return $this->belongsTo('App\Subjects');
}
The below controller will search for subject by keyword, select type or area and return value as json using toJson() and return results to view:-
public function search(Request $request)
{
//start search//
$get_Subjects = new Subject();
$get_Subjects = $get_Subjects ->newQuery();
if($request->term != '')
{
$get_Subjects->with('articles')->whereHas('articles', function ($query) use ($request){
$query->where('title', 'LIKE', '% '.$request->term.' %')
->orwhere('abstract', 'LIKE', '% '.$request->term.' %')
->orwhere('fullCitation', 'LIKE', '% '.$request->term.' %');
})
->where(function($query) use ($request){
$query->where('name', 'LIKE', '%'.$request->term.'%');
});
}if($request->area != '28')
{
// search for the selected area
$get_Subjects->with('areas')->whereHas('areas', function($query) use ($request){
$query->where('area_id', $request->area);
});
}
if($request->type!= '36')
{
// search for the selected types
$get_Subjects->with('types')->whereHas('types', function($query) use ($request){
$query->where('type_id', $request->type);
});
}
$subjects = $get_Subjects->tojson();
return View::make('public.search', compact('subjects'));
}
the issue is when i search by keyword the returned json only include related articles, and if i search by area i only get related areas()
while if i did not use json and access variable from blade i can access all related models even though it is the same query
i tried to use load() but it did not work
any help will be valuable
============Update===========
i tried using load() as follow
$subjects= $get_subjects->get();
$subjects= $subjects->load('articles', 'areas', 'types')->tojson();
when search by keyword, the json does have related relations
but they are empty
when search by area or type, the json does have related relation
which mean if i search in the subject table only which is the 1st case i wont get related model with it
please need your help

Answer 1

Have you tried adding the ->get() method before the ->toJson() method?
$subjects = $get_Subjects->get()->toJson();
get() will run the query and return models. toJson() should then work as you expect.
Update
I would write your code like this to start with. (I haven't tested this).
It seems like you are using the whereHas the wrong way. The subject table should have the area_id and type_id fields, so whereHas isn't needed... this might not be the case, but it seems like it should be based on the info you provided.
public function search(Request $request)
{
$get_Subjects = new Subject();
$get_Subjects = $get_Subjects ->newQuery();
$with = [];
if($request->term != '') {
$with[] = 'articles';
$subjects = $get_Subjects->whereHas('articles', function ($query) use ($request){
$query->where('title', 'LIKE', '% '.$request->term.' %')
->orwhere('abstract', 'LIKE', '% '.$request->term.' %')
->orwhere('fullCitation', 'LIKE', '% '.$request->term.' %');
})
->where('name', 'LIKE', '%'.$request->term.'%');
}
if($request->area != '28') {
$with[] = 'areas';
$get_Subjects->where('area_id', $request->area);
}
if($request->type!= '36') {
$with[] = 'types';
$get_Subjects->where('type_id', $request->type);
}
$subjects = $get_Subjects->with($with)->get()->toJson();
return View::make('public.search', compact('subjects'));
}