yii\rbac\PhpManager::getPermissionsByRole PHP Method

    public function getPermissionsByRole($roleName)
    {
        $result = [];
        $this->getChildrenRecursive($roleName, $result);
        if (empty($result)) {
            return [];
        }
        $permissions = [];
        foreach (array_keys($result) as $itemName) {
            if (isset($this->items[$itemName]) && $this->items[$itemName] instanceof Permission) {
                $permissions[$itemName] = $this->items[$itemName];
            }
        }
        return $permissions;
    }