It is possible with the count function, like so:

@if (count($array) > 0)
    {{-- expr --}}
@endif

The thing is the way how you are sending the data to your backend. As it seems, your are grouping by attribute (an array of ids then an array of names and so on) instead than by "class" (an array of elements that contains all the attributes in it: id, name, ...).

So, you could solve this issue in two ways.

1. Improving the way you are collecting the data in your frontend to send it to your back (recommended)
2. Handle the data in the back as it is right now.

For the first way, there are several guides/tutorials that can help you with. So, let's proceed with the second one.

public function update(Request $request, $jobId)
{
    /** This should output 2 */
    $size = count(collect($request)->get('id'));
    // Try: dd($size);

    for ($i = 0; $i < $size; $i++)
    {
        $subJob = SubJob::Find($request->get('id')[$i]);
        $subJob->job_id = $jobId;
        $subJob->name = $request->get('name')[$i];
        $subJob->size = $request->get('size')[$i];
        $subJob->medium = $request->get('medium')[$i];
        $subJob->feature = $request->get('feature')[$i];
        $subJob->qty = $request->get('qty')[$i];
        $subJob->price = $request->get('price')[$i];
        $subJob->total = $request->get('qty')[$i] * $request->get('price')[$i];
        $subJob->save();
    }
}

If $request is an Illuminate\Http\Request, it won't be directly countable.

You can count $request->all() or $request->input(), though.

thanks to this thread Laravel 5.6. JSONb column. Count array

I found whereJsonLength() that worked for my use case:

$vcount = Variation::where('user_id', user_id)->whereJsonLength('bullets', '=', 5)->count();