So recently i tried making a chat app using React and firebase, to learn these tools. It goes very well, but for some reason it seems that whenever the database is active it spams read on the collection, even with no changes. I suspect some element is rerendering in an infinite loop, but i can't seem to fix it. Any suggestions for how i can display messages and only update whenever a new change is made to the collection?
import React, { useRef, useState } from 'react';
import firebase from 'firebase/compat/app';
import 'firebase/compat/auth';
import 'firebase/compat/firestore';
import { useAuthState } from 'react-firebase-hooks/auth';
import { useCollectionData } from 'react-firebase-hooks/firestore';
import './App.css';
import Navbar from './Navbar';
firebase.initializeApp({
// My configs are here
})
const auth = firebase.auth();
const firestore = firebase.firestore();
function App() {
const [user] = useAuthState(auth);
return (
<>
<div className="App">
<Navbar />
</div>
<section className="place-content-end">
{user ? <ChatRoom /> : <SignIn />}
<SignOut />
</section>
</>
);
}
function SignIn() {
const signInWithGoogle = () => {
const provider = new firebase.auth.GoogleAuthProvider();
auth.signInWithPopup(provider);
}
return (
<>
<button className="sign-in ml-20 pl-5" onClick={signInWithGoogle}>Sign in with Google to join! </button>
<p className="ml-20 pl-5">Welcome to the chat!</p>
</>
)
}
function SignOut() {
return auth.currentUser && (
<button className="sign-out ml-20 pl-5" onClick={() => auth.signOut()}>Sign Out</button>
)
}
function ChatRoom() {
const messagesRef = firestore.collection('messages');
const query = messagesRef.orderBy('createdAt').limit(50);
const [messages] = useCollectionData(query, { idField: 'id' });
return (
<>
<div className="App ml-20 pl-5">
<h1>HELLO WORLD!</h1>
<main>
{messages && messages.map(msg => <DisplayMessage key={msg.id} message={msg} />)}
</main>
</div>
</>
);
}
function DisplayMessage(props) {
const { text, uid } = props.message;
return (<>
<div>
<p>{text}</p>
</div>
</>)
}
export default App;
And my firebase looks like this after a few minutes online on my local server
Try this and see if it works:
import React, { useRef, useState, useEffect } from "react";
import firebase from "firebase/compat/app";
import "firebase/compat/auth";
import "firebase/compat/firestore";
import { useAuthState } from "react-firebase-hooks/auth";
import { useCollectionData } from "react-firebase-hooks/firestore";
import "./App.css";
import Navbar from "./Navbar";
firebase.initializeApp({
// My configs are here
});
const auth = firebase.auth();
const firestore = firebase.firestore();
function App() {
const [user] = useAuthState(auth);
return (
<>
<div className="App">
<Navbar />
</div>
<section className="place-content-end">
{user ? <ChatRoom /> : <SignIn />}
<SignOut />
</section>
</>
);
}
function SignIn() {
const signInWithGoogle = () => {
const provider = new firebase.auth.GoogleAuthProvider();
auth.signInWithPopup(provider);
};
return (
<>
<button className="sign-in ml-20 pl-5" onClick={signInWithGoogle}>
Sign in with Google to join!{" "}
</button>
<p className="ml-20 pl-5">Welcome to the chat!</p>
</>
);
}
function SignOut() {
return (
auth.currentUser && (
<button className="sign-out ml-20 pl-5" onClick={() => auth.signOut()}>
Sign Out
</button>
)
);
}
function ChatRoom() {
const [messages, setMessages] = useState([]);
useEffect(() => {
const messagesRef = firestore.collection("messages");
const query = messagesRef.orderBy("createdAt").limit(50);
const [data] = useCollectionData(query, { idField: "id" });
setMessages(data);
}, []);
return (
<>
<div className="App ml-20 pl-5">
<h1>HELLO WORLD!</h1>
<main>
{messages.length > 0 &&
messages.map((msg) => (
<DisplayMessage key={msg.id} message={msg} />
))}
</main>
</div>
</>
);
}
function DisplayMessage(props) {
const { text, uid } = props.message;
return (
<>
<div>
<p>{text}</p>
</div>
</>
);
}
export default App;
I added useEffect in line 1. And changed your ChatRoom component.
Quick explanation
useEffect is part of the lifecycle of a Function Component. You give it a function to execute whenever the component mounts or props or state of the component changes. You decide this by what you add as the second argument of the useEffect call. If you give it an [] (empty array), it will only execute when the component is mounted. If you give, for example, [messages] (which a state created by useState) then the function will execute on component mount AND whenever messages change. React keeps track of this for you, this is why React is called react, if data changes it reacts to it and renders accordingly.
The above explanation is the basics of it. But there is also one more cool thing it can do:
If you return a function from inside of useEffect, this function will execute when the component is UNmounted. Like so:
useState(() => {
console.log("Component mounted");
return () => {
console.log("Component unmounted");
};
},[]);
In Class Components we have similar functions, they are called: componentDidMount, componentWillUnmount and others.You can read about it here React State & Lifecyle
Related
I am very new to React and was trying to make a context in React so that in my notes app such that I can trigger my custom made alert for relevant user activity but when I am trying to use the values from the context using useContext I am getting error : "Cannot destructure property 'alert' of 'Object(...)(...)' as it is undefined."
Here's the code:-
Creating Context
import React from 'react';
const AlertContext = React.createContext(null);
export default AlertContext;
Populating Value to the Context
import React,{useState} from 'react';
import AlertContext from "./AlertContext";
const ShowAlert = (props)=>{
const [alert,setAlert] = useState(null);
const showAlert = (message,type)=>{
setAlert({
msg:message,
type:type
})
setTimeout(()=>{
setAlert(null);
},3000);
}
return(
<AlertContext.Provider value={{alert,showAlert}}>
{props.children}
</AlertContext.Provider>
)
}
export default ShowAlert;
Trying to use the values
import React, { useContext } from "react";
import { Navbar, Button, Nav } from "react-bootstrap";
import { Link, useHistory } from "react-router-dom";
import ShowAlert from "../contexts/ShowAlert";
import MyAlert from "./MyAlert";
function Header() {
const {alert} = useContext(ShowAlert);
let history = useHistory();
const handleLogout = () => {
localStorage.removeItem("token");
history.push("/login");
};
return (
<>
<header>
<Navbar collapseOnSelect expand="lg" className="header">
<Navbar.Brand className="heading">
<Link to="/" className="headerLink">
Note Cloud
</Link>
<i className="fas fa-cloud-upload-alt cloudIcon"></i>
</Navbar.Brand>
<Navbar.Toggle aria-controls="responsive-navbar-nav" />
<Navbar.Collapse id="responsive-navbar-nav">
<Nav className="me-auto"></Nav>
{localStorage.getItem("token") && (
<Nav>
<Nav.Link>
<Button variant="primary" size="lg" onClick={handleLogout}>
Logout
</Button>
</Nav.Link>
</Nav>
)}
</Navbar.Collapse>
</Navbar>
</header>
<MyAlert alert={alert}></MyAlert>
</>
);
}
export default Header;
Edit:- MyAlert Component
import React, { useContext } from "react";
import { Alert } from "react-bootstrap";
import ShowAlert from "../contexts/ShowAlert";
const MyAlert = (props) => {
const {alert} = useContext(ShowAlert);
const capitalize = (word) => {
if(word==="danger")
{
word = "error";
}
const lower = word.toLowerCase();
return lower.charAt(0).toUpperCase() + lower.slice(1);
};
return (
<div style={{ height: "50px" , width:"100%"}}>
{alert && (
<Alert
variant={alert.type}
>
<Alert.Heading>{capitalize(alert.type)}</Alert.Heading>
<p>{capitalize(alert.msg)}</p>
</Alert>
)}
</div>
);
};
export default MyAlert;
Error That I am getting
Try doing the Context like this instead of null.
import React from "react";
const AlertContext = React.createContext({
alert: {},
setAlert: (alert) => {},
});
export default
i think your export is the fail
export const AlertContext = React.createContext({})
or as well you can try:
< AlertContext.Consumer>
{(context) => {
console.log(context)
}}
</AlertContext.Consumer>
I am working with a navigation bar that should be able to switch between multiple chat rooms using react and react-firebase-hooks. (https://github.com/CSFrequency/react-firebase-hooks)
However, the chat room will infinitely re-render itself when I choose a room in nav-bar.
I initially thought this is a router issue, but having each rooms sharing the same url, the issue persists.
Right now, when I choose a room using the nav bar, it will send that room number back to App.js using a callback function. App.js will pass that room number to ChatRoom.js, which will get the data from firestore, and re-render itself.
I struggled for several days trying to find anything that could cause the infinite loop with minimal success. Any help would be appreciated!
ChatRoom.js
import React, { useMemo, useRef, useState } from 'react';
import { withRouter } from 'react-router';
import { useCollectionData, useDocument, useDocumentData } from 'react-firebase-hooks/firestore';
import firebase, { firestore, auth } from '../Firebase.js';
import ChatMessage from './ChatMessage';
const ChatRoom2 = (props) => {
console.log("chat room rendered");
function saveQuery(){
const channelid= props.channelid;
const messagesRef = firestore.collection('messages').doc(channelid).collection('chats');
const query = messagesRef.orderBy('createdAt').limitToLast(25);
return [messagesRef,query];
}
var returnedVal = useMemo(()=>saveQuery , [props.channelid]);
const messagesRef = returnedVal[0];
const query = returnedVal[1];
const [messages] = useCollectionData(query, { idField: 'id' });
const [formValue, setFormValue] = useState('');
const sendMessage = async (e) => {
e.preventDefault();
console.log(messagesRef);
console.log(query);
console.log(messages);
const { uid, photoURL } = auth.currentUser;
await messagesRef.add({
text: formValue,
createdAt: firebase.firestore.FieldValue.serverTimestamp(),
uid,
photoURL
})
setFormValue('');
}
return (<>
<main>
{messages && messages.map(msg => <ChatMessage key={msg.id} message={msg} />)}
</main>
<form onSubmit={sendMessage}>
<input value={formValue} onChange={(e) => setFormValue(e.target.value)} placeholder="say something nice" />
<button type="submit" disabled={!formValue}>🕊️</button>
</form>
</>)
}
export default ChatRoom2;
ChatList.js (nav bar)
const ChatList = (props) => {
console.log("list rendered");
const query = firestore.collection('users').doc(auth.currentUser.uid).collection('strangers').orderBy('channelID').limitToLast(10);
//console.log(query);
const [channelidArr] = useCollectionData(query, { idField: 'id' });
return (
<div>
{channelidArr && channelidArr.map(channelid =>
<div>
<button onClick={() => props.parentCallback(channelid.channelID)}>{channelid.channelID}</button>
<br />
</div>)}
</div>
);
};
export default ChatList;
App.js
import React, { useRef, useState } from 'react';
import {
BrowserRouter,
Switch,
Route,
Link
} from "react-router-dom";
//import './App.css';
import firebase, { firestore, auth } from './Firebase.js';
import { useAuthState } from 'react-firebase-hooks/auth';
import { useCollectionData } from 'react-firebase-hooks/firestore';
import ChatList from './components/ChatList.js';
import FindNew from './components/FindNew.js';
import Footer from './components/Footer.js';
import Profile from './components/Profile.js';
import ChatRoom2 from './components/ChatRoom2.js';
import SignOut from './components/SignOut.js';
import SignIn from './components/SignIn.js';
import SignUp from './components/SignUp.js';
import ChatRoom from './components/ChatRoom.js';
function App() {
console.log('App rendered');
const [user] = useAuthState(auth);
const [roomNum, setRoomNum] = useState([]);
const callbackFunction = (childData) => {
setRoomNum(childData);
};
return (
<div className="App">
<header>
<h1>⚛️🔥💬</h1>
<SignOut auth={auth} />
</header>
<BrowserRouter >
<Footer />
<Switch>
<Route path="/profile">
<Profile />
</Route>
<Route path="/new">
<FindNew />
</Route>
<Route path="/signup">
{() => {
if (!user) {
return <SignUp />;
} else {
return null;
}
}}
</Route>
<Route path="/direct">
{user ?
<div>
<ChatList parentCallback={callbackFunction} />
<ChatRoom2 channelid={roomNum} />
</div> : <SignIn />}
</Route>
</Switch>
</BrowserRouter>
</div>
);
};
export default App;
Issue Summary
useCollectionData memoizes on the query parameter but since a new query reference was declared each render cycle the firebase hook was rerun and updated collection and rerendered the component.
const { channelid } = props;
const messagesRef = firestore
.collection('messages')
.doc(channelid)
.collection('chats');
const query = messagesRef // <-- new query reference
.orderBy('createdAt')
.limitToLast(25);
const [messages] = useCollectionData(
query, // <-- reference update trigger hook
{ idField: 'id' },
);
Solution
query has only a dependency on the channelid prop value, so we can memoize the query value and pass a stable value reference to the useCollectionData hook.
const { channelid } = props;
const query = useMemo(() => {
const messagesRef = firestore
.collection('messages')
.doc(channelid)
.collection('chats');
const query = messagesRef.orderBy('createdAt').limitToLast(25);
return query;
}, [channelid]);
const [messages] = useCollectionData(
query, // <-- stable reference
{ idField: 'id' },
);
I'm new to React and I'm currently setup my first project using Gatsby. Essentially I'm creating a website that use an API created with Strapi. So far, I would like to load the navbar items using an API call like that: http://localhost:3001/sections, where for sections, I mean the items of the navbar.
For doing so, I have defined an Index page like that:
import React from "react"
import Layout from "../components/layout/layout"
import SEO from "../components/layout/seo"
import BGTState from "../context/bgt/bgtState"
import "../styles/css/begreentannery.css"
const IndexPage = () => {
return (
<BGTState>
<Layout>
<SEO title="Home" />
</Layout>
</BGTState>
)
}
export default IndexPage
the BGTState contains the getSections() method that is used inside Layout:
import React, { useContext, useEffect } from "react"
import PropTypes from "prop-types"
import { injectIntl } from "gatsby-plugin-intl"
import BGTContext from "../../context/bgt/bgtContext"
import { Spinner } from "react-bootstrap"
import Footer from "./footer"
import SearchState from "../../context/search/SearchState"
import Search from "../../components/search"
import NavbarMobile from "../../components/layout/navbarMobile"
import NavbarDesktop from "../../components/layout/navbarDesktop"
const Layout = ({ children, intl }) => {
const bgtContext = useContext(BGTContext)
const { loading, getSections, sections } = bgtContext
useEffect(() => {
getSections()
//eslint-disable-next-line
}, [])
return !loading ? (
<>
<NavbarMobile sections={sections} />
<NavbarDesktop sections={sections} />
<SearchState>
<Search />
<div className="container-fluid">
<div className="main">
{children}
<Footer />
</div>
</div>
</SearchState>
</>
) : (
<div className="container" style={{ height: "100vh" }}>
<div className="row h-100 justify-content-center align-items-center">
<Spinner animation="grow" />
</div>
</div>
)
}
Layout.propTypes = {
children: PropTypes.node.isRequired,
}
export default injectIntl(Layout)
the problem is in the code above, essentially I call useEffect hook which grab the sections from the API. So, until the sections are downloaded, I stop the code like so:
return !loading ? (
this is the getSections() method inside BGTState:
const getSections = async () => {
try {
setLoading()
const res = await axios.get(
`${process.env.API_URL}/sections?_sort=order:ASC`
)
dispatch({
type: GET_SECTIONS,
payload: res.data,
})
} catch (err) {
dispatch({
type: GET_SECTIONS,
payload: err.response.msg,
})
}
}
in the Index page all works fine, but the problem is in the CollectionsPage, infact I have this structure:
import React from "react"
import { injectIntl } from "gatsby-plugin-intl"
import Layout from "../components/layout/layout"
import SEO from "../components/layout/seo"
import BGTState from "../context/bgt/bgtState"
import CollectionState from "../context/collection/collectionState"
import Collection from "../components/collection"
const CollectionsPage = ({ intl }) => {
return (
<BGTState>
<Layout>
<SEO
lang={intl.locale}
title={`${intl.formatMessage({ id: "collections" })}`}
/>
<CollectionState>
<Collection id={1} />
</CollectionState>
</Layout>
</BGTState>
)
}
export default injectIntl(CollectionsPage)
essentially, the component <CollectionState> isn't mounting 'cause in Layout there is the async call on getSections().
So in Collection component, I have:
import React, { useContext, useEffect } from "react"
import CollectionContext from "../context/collection/collectionContext"
import { Link } from "gatsby"
const Collection = ({ id }) => {
const collectionContext = useContext(CollectionContext)
const { loading, collection, getCollection } = collectionContext
useEffect(() => {
getCollection(id)
}, [])
if (loading) return React.Fragment
return (
<div className="container">
<div className="row">
{/*
<img
src={`${process.env.API_URL}${collection.feature_media.url}`}
className="w-100 mt-2 mb-2"
alt={""}
/>*/}
<Link to="#" className="bg-caption bg-no-underline">
fall/winter 20/21
</Link>
</div>
</div>
)
}
export default Collection
which generate that error:
and of course getCollection is not called and will generate other errors in the Collection component
How can I revisit this mechanism? Essentially I have to:
Load all the sections
Load all the components
Is it possible to consume multiple context in one component which is from two different component . I tried It but but I am not getting value
This is the component which consume two different context
import React from "react";
import { UserContext } from "../App";
import { NewContext } from "./CompY";
const CompX = () => {
return (
<div>
<UserContext.Consumer>
{(user) => {
return (
<>
<NewContext.Consumer>
{(username) => {
return (
<>
<h1>Hello {user.username} </h1>
<h2>This is CompX in the {user.name} component</h2>
<h3>This is {username} </h3>
</>
);
}}
</NewContext.Consumer>
</>
);
}}
</UserContext.Consumer>
</div>
);
};
export default CompX;
Here is the App.Js
You can use multiple contexts in functional component easily with useContext
Consumer and provider is bad practice in functional component
import { UserContext } from "../App";
import { NewContext } from "./CompY";
const CompX = () => {
const user = useContext(UserContext);
const newUser = useContext(NewContext);
....
}
In my SPA, I am utilizing react hooks and context API. I need to persist the current state of the component view rendered using the context API so that I can implement the global component conditional rendering through the application.
I have two views on a single dashboard page: overview & detail. The button triggers the global state change and the view should be fixed on the state value even on page refresh.
Here's my code snippets:
AppRoutes file
import React, { useState } from "react";
import { Router, Route, Switch } from "react-router-dom";
import history from "../utils/history";
import { PyramidProvider } from "../context/pyramidContext";
import Dashboard from "../pages/dashboard/Dashboard";
const AppRoutes = () => {
return (
<div>
<React.Suspense fallback={<span>Loading...</span>}>
<Router history={history}>
<Switch>
<PyramidProvider>
<Route path="/" component={Dashboard} />
</PyramidProvider>
</Switch>
</Router>
</React.Suspense>
</div>
);
};
export default AppRoutes;
Dashboard page
import React, { useState, useEffect, useContext } from "react";
import { PyramidContext } from "../../context/pyramidContext";
import PyramidDetail from "../../components/pyramidUI/pyramidDetail";
import PyramidOverview from "../../components/pyramidUI/pyramidOverview";
const Dashboard = (props) => {
const { info, setInfo } = useContext(PyramidContext);
return (
<React.Fragment>
{info.uiname === "overview" ? <PyramidOverview /> : <PyramidDetail />}
</React.Fragment>
);
};
export default Dashboard;
Overview component
import React, { useState, useContext } from "react";
import { PyramidContext } from "../../context/pyramidContext";
const Overview = (props) => {
const { info, setInfo } = useContext(PyramidContext);
return (
<div className="d-flex flex-column dashboard_wrap">
<main>
<div className="d-flex">
<button
onClick={() => setInfo({ uiname: "detail", pyramidvalue: 1 })}
>
change view
</button>
</div>
</main>
</div>
);
};
export default Overview;
Detail component
import React, { useContext } from "react";
import { PyramidContext } from "../../context/pyramidContext";
// import axios from "axios";
const Detail = (props) => {
const { info, setInfo } = useContext(PyramidContext);
return (
<div className="d-flex flex-column dashboard_wrap">
<h2>Detail View</h2>
<div>
<button
type="button"
onClick={() => setInfo({ uiname: "overview", pyramidvalue: 0 })}
>
Back
</button>
</div>
</div>
);
};
export default Detail;
Context File
import React, { createContext, useEffect, useReducer } from "react";
let reducer = (info, newInfo) => {
return { ...info, ...newInfo };
};
const initialState = {
uiname: "overview",
pyramidvalue: 0,
};
const localState = JSON.parse(localStorage.getItem("pyramidcontent"));
const PyramidContext = createContext();
function PyramidProvider(props) {
const [info, setInfo] = useReducer(reducer, initialState || localState);
useEffect(() => {
localStorage.setItem("pyramidcontent", JSON.stringify(info));
}, [info]);
return (
<PyramidContext.Provider
value={{
info,
setInfo,
}}
>
{props.children}
</PyramidContext.Provider>
);
}
export { PyramidContext, PyramidProvider };
I click the button to render a detail view and soon as the page is refreshed, the component changes its view to overview instead of sticking around to detail. I checked the local storage values, and it is being updated properly, but still, the component view does not persist as per the value.
I am unable to understand where I am doing wrong, any help to resolve this issue, please? Thanks in advance.
You're never using the value of localStage in your info state,
you should replace your code with:
const [info, setInfo] = useReducer(reducer, localState || initialState);