firebase数据不添加在array ion 3中

Question

这是我的ts文件

 $path_to_firebase_cm = 'https://fcm.googleapis.com/fcm/send';
    $token=array($token);
   $fields = array(
        'registration_ids' => $token,
        'priority' => 10,
        'data'=>$send_notification ,
        'notification' => array('title' => $type_of_notification, 'body' => $title ,'sound'=>'Default'),
    );
    $headers = array(
        'Authorization:key=' .'your server key' ,
        'Content-Type:application/json'
    );  

    // Open connection  
    $ch = curl_init('https://fcm.googleapis.com/fcm/send'); 
    // Set the url, number of POST vars, POST data
    curl_setopt($ch, CURLOPT_URL, $path_to_firebase_cm); 
    curl_setopt($ch, CURLOPT_POST, 1);
    curl_setopt($ch, CURLOPT_HTTPHEADER, $headers);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, TRUE);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, false);
    curl_setopt($ch, CURLOPT_IPRESOLVE, CURL_IPRESOLVE_V4 );
    curl_setopt($ch, CURLOPT_POSTFIELDS, json_encode($fields));
    // Execute post   
    $result = curl_exec($ch); 
    // Close connection      
    curl_close($ch);
    return $result;

当我每次运行app时显示Error：Uncaught（在promise中）：TypeError：无法设置未定义的属性'items'