Laravel old helper for database models

old_helper.php

if (! function_exists('old_helper')) {

    /**
     * Retrieve an old input item and set a
     * default value with helper
     *
     * @param $oldKey
     * @param null $target
     * @param null $targetKey
     * @param callable|null $callback
     * @return mixed
     */
    function old_helper($oldKey, $target = null, $targetKey = null, callable $callback = null)
    {

        $value = data_get($target, $targetKey);

        if (! is_null($callback) && ! is_null($value)) {

            $value = $callback($value);
        }

        return old($oldKey, $value);
    }

}

sample.php

$user = \App\User::find(1);

// echo old name only
echo old_helper('name'); 

// echo name from user if old name not exists
echo old_helper('name', $user, 'name');

// format values in a callback functions - this works only if target key is not null
echo old_helper('name', $user, 'created_at', function($value) {
  return $value->format('d/m/Y')
});

// echo value from a relationship
echo old_helper('name', $user, 'roles.name');
echo old_helper('name', $user, 'long.example.relationships');

// echo null if target key not exists
echo old_helper('name', $user, 'nonexistent.key.value');