"querySnapshot.forEach is not a function" in firestore

Question

I'm trying to do a query to the database, to get all documents of sub-collection "roles" to redirect to different routes.

let userRef1 = db.collection('users').doc(currentUser.uid).collection('roles')
let cont = 0
let rol = ''
let rolStatus = ''

userRef1.get().then(function(querySnapshot) {                                                                                                                               
  querySnapshot.forEach(function(doc) {                                                                                                                            

    cont++ 
    rol = doc.data().rol
    rolStatus = doc.data().status                                         
  });                                      

Solution 1

import { firestore } from "../../firebase";
export const loadCategories = () => {
  return (dispatch, getState) => {
    firestore
      .collection("CATEGORIES")
      .get()
      .then((querySnapshot) => {
        if (!querySnapshot.empty) {
          querySnapshot.forEach((doc) => {
            console.log(doc.id, "=>", doc.data());
          });
        }
      })
      .catch((error) => {
        console.log(error);
      });
  };
};

Solution 2

I have a collection of users including uid just like yours. And for each user, it contains a sub-collection called friends.

Currently, I'm using the following code for my project without having any issues.

module.exports = ({ functions, firestore }) => {
  return functions.firestore.document('/users/{uid}').onDelete((event) => {

    const userFriendsRef = getFriendsRef(firestore, uid);

     userFriendsRef.get().then(snapshot => {
       if (snapshot.docs.length === 0) {
         console.log(`User has no friend list.`);
         return;
      } else {
        snapshot.forEach(doc => {
          // call some func using doc.id
        });
      }
     }
  }
};

function getFriendsRef(firestore, uid) {
  return firestore.doc(`users/${uid}`).collection('friends');
}

Give it a try to fix your code from

db.collection('users').doc(currentUser.uid).collection('roles')

to

db.doc(`users/${currentUser.uid}`).collection('roles')

Solution 3

It is not clear what you are doing with the rol and status variables. You have declared them as though you are storing a single value, yet you are returning an array of roles and iterating through them.

With regards to getting the results, if your browser supports ES6, then you could do the following:

let userRef1 = db.collection(`users/${currentUser.uid}/roles`)
let cont = 0
let rol;
let rolStatus;

return userRef1.get()
  .then(querySnapshot => {
    // Check if there is data
    if(!querySnapshot.empty) {
      // Create an array containing only the document data
      querySnapshot = querySnapshot.map(documentSnapshot => documentSnapshot.data());
      querySnapshot.forEach(doc => {
        let {rol, status} = doc;
        console.log(`rol: ${rol} - status: ${status}`);
      });
    } else {
      console.log('No data to show');
    }
  })
  .catch(err => {
    console.error(err);
  }); 

Please note: I've only tested this with the Node SDK

Solution 4

// Firebase App (the core Firebase SDK) is always required and must be listed first
import * as firebase from "firebase/app";
// Add the Firebase products that you want to use
import "firebase/auth";
import "firebase/firestore";
const firebaseConfig = {
  apiKey: "AIzaSyDNdWutrJ3Axpm-8ngNhzkzcw1g3QvkeFM",
  authDomain: "books-7bd8b.firebaseapp.com",
  databaseURL: "https://books-7bd8b.firebaseio.com",
  projectId: "books-7bd8b",
  storageBucket: "books-7bd8b.appspot.com",
  messagingSenderId: "385706228283",
  appId: "1:385706228283:web:a3c2c9585dd74d54693a1e",
};
firebase.initializeApp(firebaseConfig);
export const firebaseAuth = firebase.auth();
export const firestore = firebase.firestore();
export default firebase;

View more solutions

Comments

[Jason Berryman]

You can shorten this further to let userRef1 = db.collection(<bt>users/${currentUser.uid}/roles<bt>). I can't format this properly in a comment. Please replace <bt> with a backtick

[Ivo Mori]

Welcome to Stack Overflow. Note that you can edit your answer; there's no need to post another answer for the same question. I suggest you either remove this answer or your other answer and then edit the remaining answer as needed. Also, it's much better to enhance your code-only-answer with some explanations. Have a look at How do I write a good answer?.