问Firestore的Firebase云函数未触发

EN

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

exports.sendNotification = functions.firestore
  .document('chats/{chatID}')
  .onWrite((data, context) => {
    // Get an object representing the document
    console.log('chat triggered');
    // perform desired operations ...

    // See documentation on defining a message payload.
    var message = {
      notification: {
        title: 'Hello World!',
        body: 'Hello World!'
      },
      topic: context.params.chatID
    };

    // Send a message to devices subscribed to the provided topic.
    return admin.messaging().send(message)
      .then((response) => {
        // Response is a message ID string.
        console.log('Successfully sent message:', response);
        return true
      })
      .catch((error) => {
        console.log('Error sending message:', error);
      });

  });