Question

这是错误；

TypeError：无法读取未定义的属性“ val” 在exports.sendNotification.functions.database.ref.onWrite（/user_code/index.js:14:19）在对象。（/user_code/node_modules/firebase-functions/lib/cloud-functions.js:112:27）在下（本机）在/user_code/node_modules/firebase-functions/lib/cloud-functions.js:28:71 在__awaiter（/user_code/node_modules/firebase-functions/lib/cloud-functions.js:24:12）在cloudFunction（/user_code/node_modules/firebase-functions/lib/cloud-functions.js:82:36）在/var/tmp/worker/worker.js:728:24 在process._tickDomainCallback（internal / process / next_tick.js：135：7）

这是我的代码：

exports.sendNotification = functions.database.ref('/notifications/{user_id}/{notification_id}').onWrite((change, context) => {

  const user_id = context.params.user_id;
  const notification = context.params.notification;

  console.log('We have a notification to send to : ', user_id);

  if(!context.data.val()){
    return console.log('A notification has been deleted from the database:', notification_id);
  }

  const deviceToken = admin.database().ref(`/Users/${user_id}/deviceToken`).once('value');

  return deviceToken.then(result => {

    const token_id = result.val();

    const payload = {
      notification: {
        title : "Friend Request",
        body : "You've receieved a new Friend Request",
        icon : "default"
      }
    };

    return admin.messaging().sendToDevice(token_id, payload).then(response => {

      console.log('This is the notification Feature');

    });

  });



});

Answer 1

使用apr-util代替context.data.val()

请测试此功能：

change.after.exists()

Answer 2

代替

const token_id = result.val();

尝试

const token_id = result.after.data();

Firebase云功能-无法读取未定义的属性'val'

2 个答案: