TypeError: 'Reference' object 在 java 脚本中不可迭代

Question

i want to retrieve data from firebase to javascrip. how i get some data and get output data to the variable. this is my code

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

admin.initializeApp();

exports.sendNotificationUser = functions.firestore
    .document('donorRequests/{donorRequestId}')
    .onWrite((snapshot, context) => {
        var tokens = [];
        // var accounts = admin.firestore().collection('accounts').where("bloodType", '==', record.bloodType).where("rhesus", '==', record.rhesus).get();
        for (const i of accounts) {
            tokens.push(account.val().token);
        }
        var payload = {
            "notification":{
                'title': 'Hai Pahlawan!',
                'body': 'Seseorang butuh kamu, yuk kita bantu :)'
            }
        }
        admin.messaging().sendToDevice(tokens, payload);                
    })

and the error message is

TypeError: accounts is not iterable

anyone can help me

Answer 1

As you can see from the API documentation , Firestore's query.get() returns a promise that resolves with a QuerySnapshot object. You're going to have to use that promise to wait for the query to complete, then iterate the documents in the QuerySnapshot object.

I suggest starting with the documentation to learn how queries work with Firestore, and see some examples.

Also, you're going to have to learn how JavaScript promises work with Cloud Functions. You must deal with the promise from the query and the promise from sendToDevice correctly, or the function won't work. See the documentation for details.