src/Policies/MenuItemPolicy.php
protected function checkPermission(User $user, $model, $action)
    {
        if (self::$permissions == null) {
            self::$permissions = Voyager::model('Permission')->all();
        }

        if (self::$datatypes == null) {
            self::$datatypes = Voyager::model('DataType')::all()->keyBy('slug');
        }

        $regex = str_replace('/', '\/', preg_quote(route('voyager.dashboard')));
        $slug = preg_replace('/'.$regex.'/', '', $model->link(true));
        $slug = str_replace('/', '', $slug);

        if ($str = self::$datatypes->get($slug)) {
            $slug = $str->name;
        }

        if ($slug == '') {
            $slug = 'admin';
        } elseif ($slug == 'compass' && !\App::environment('local') && !config('voyager.compass_in_production', false)) {
            return false;
        }

        if (empty($action)) {
            $action = 'browse';
        }

        // If permission doesn't exist, we can't check it!
        if (!self::$permissions->contains('key', $action.'_'.$slug)) {
            return true;
        }

        return $user->hasPermission($action.'_'.$slug);
    }
protected function checkPermission(User $user, $model, $action)
    {
        if (self::$permissions == null) {
            self::$permissions = Voyager::model('Permission')->all();
        }

        if (self::$datatypes == null) {
            self::$datatypes = Voyager::model('DataType')::all()->keyBy('slug');
        }

        $regex = str_replace('/', '\/', preg_quote(route('voyager.dashboard')));
        $slug = preg_replace('/'.$regex.'/', '', $model->link(true));
        $slug = str_replace('/', '', $slug);

        if ($str = self::$datatypes->get($slug)) {
            $slug = $str->name;
        }

        if ($slug == '') {
            $slug = 'admin';
        } elseif ($slug == 'compass' && !\App::environment('local') && !config('voyager.compass_in_production', false)) {
            return false;
        }

        if (empty($action)) {
            $action = 'browse';
        }

        // If permission doesn't exist, we can't check it!
        if (!self::$permissions->contains('key', $action.'_'.$slug)) {
            return true;
        }

        return $user->hasPermission($action.'_'.$slug);
    }
Check if user has an associated permission.

@param User   $user
@param object $model
@param string $action

@return bool