Question

我正在尝试制作Firebase推送通知应用程序并且在上传脚本时出现此错误。我不了解无法读取属性错误

TypeError: Cannot read property 'from' of undefined
   at admin.firestore.collection.doc.collection.doc.get.then.queryResult 
    (/user_code/index.js:16:48)
    at process._tickDomainCallback (internal/process/next_tick.js:135:7)

这是我的node.js脚本

'use-strict'

const functions = require('firebase-functions');
const admin = require('firebase-admin');
admin.initializeApp(functions.config().firebase);

 exports.sendNotification = 
  functions.firestore.document("Users/{user_id}/Notifications/{notification_id}")
    .onWrite((change,context)=> {

const user_id = context.params.user_id;
const notification_id = context.params.notification_id;

console.log("User ID : " + user_id + " | Notification ID : " + notification_id);

return admin.firestore().collection("Users").doc(user_id).collection("NotificationsN").doc(notification_id).get().then(queryResult =>{

    const from_user_id = queryResult.data().from;

    const from_data = admin.firestore().collection("Users").doc(from_user_id).get();
    const to_data = admin.firestore().collection("Users").doc(user_id).get();

    return promise.all([from_data, to_data]).then(result =>{

      const from_name = result[0].data().name;
      const to_name = result[1].data().name;

      console.log("FROM : " + from_name +" TO : " + to_name)
      return null;
    }).catch(error => {
   console.error(error);
  res.error(500);
 });

  }).catch(error => {
  console.error(error);
  res.error(500);
  });
 });

Answer 1

您的代码中有一个错字，试图从子集合中读取文档：

return admin.firestore().collection("Users").doc(user_id).collection("NotificationsN").doc(notification_id).get().then(queryResult =>{

注意N中的NotificationsN吗？触发该功能的代码中不存在

functions.firestore.document("Users/{user_id}/Notifications/{notification_id}")

要解决该错误，只需删除结尾的N，然后保留：

return admin.firestore().collection("Users").doc(user_id).collection("Notifications").doc(notification_id).get().then(queryResult =>{

但是请注意，整个操作是不必要的：您正在（重新）加载触发该功能的文档。该文档已通过change.after传递到您的函数中，因此您不必重新加载它。您可以直接从那里直接使用它：

from_user_id = change.before.data().from;

TypeError：无法读取未定义错误的属性“ from”

1 个答案: