We can pass variables to the view by using the second parameter inside the loadView() method.
$sheet->loadView('view', array('key' => 'value'));
Alternatively you can use the with() method which works the same as with Laravel views.
// Using normal with()
$sheet->loadView('view')
->with('key', 'value');
// using dynamic with()
$sheet->loadView('view')
->withKey('value');