无法从反应图表中的 firebase 获取数据

Question

I'm using ApexChartJs for my react project, but when I tried to fetch dynamic data from my firebase database, then show me undefined .

here is my part of code from my project:

import React, { useEffect, useState } from "react";
import Chart from "react-apexcharts";
import { auth, db } from "./firebase";
import { useCollection } from "react-firebase-hooks/firestore";


  const [dataPoint, setDataPoint] = useState([]);
  const query = db.collection("data");
  const [snapshot, loading, error] = useCollection(query);
  const [series, setSeries] = useState([]);

  useEffect(() => {
    setSeries([
      {
        name: "Desktops",
        data: snapshot?.docs.map((doc) => doc.data().value),
      },
    ]);
  }, [snapshot]);

  console.log(series);

data in the firebase look like:

firebase configure file:

import firebase from "firebase";

// For Firebase JS SDK v7.20.0 and later, measurementId is optional
const firebaseConfig = {
  apiKey: "AIzaSyC2mfjPdIdXxGgJFqqVviw32xoaEMxxxxxx",
  authDomain: "chart-app-4591b.firebaseapp.com",
  projectId: "chart-app-4591b",
  storageBucket: "chart-app-4591b.appspot.com",
  messagingSenderId: "995691438244",
  appId: "1:995691438244:web:6d945f72ff51d444664631",
  measurementId: "G-2B9ZFG6E33",
};

const app = firebase.initializeApp(firebaseConfig);

const db = app.firestore();
const provider = new firebase.auth.GoogleAuthProvider();
const auth = firebase.auth;

export { db, provider, auth };

Answer 1

If your firebase app is well set-up and configured appropriately, the main issue that may lead an undefined query result is that the result are still being loaded.

To overcome this, you should update your series state whenever the loading property changes (along with query result snapshot changes):

  const query = db.collection("data");
  const [snapshot, loading, error] = useCollection(query);

  useEffect(() => {
    setSeries([
      {
        name: "Desktops",
        data: snapshot?.docs.map((doc) => doc.data().value),
      },
    ]);
  }, [loading, snapshot]);

You should provide alternative error handling as well for state update.

Update (per the permission error)

A common error source would be the lack of privileges to read and write from the configured Firestore DB highlighted by below error message:

FirebaseError: Missing or insufficient permissions

To allow all reads and writes for test only mode (should never be the case for a production system) , you can set below Security Rules for the database:

// Allow read/write access to all users under any conditions
service cloud.firestore {
  match /databases/{database}/documents {
    match /{document=**} {
      allow read, write: if true;
    }
  }
}

You can read more on Cloud Firestore Security Rules in the official documentation .