RxFire in ReactJS using Firebase Firestore and Authentication
Introduction to Create React App, Firebase, and RxFire. RxFire provides a set of observable creation methods. You simply call a function with some parameters to receive an RxJS observable. With that observable in hand you can use any operators provided by RxJS to transform the stream as you like.

Alex Patterson

 | Published:  April 26, 2019
 | Updated:  October 15, 2019
GitHub Source
RxFire in ReactJS using Firebase Firestore and Authentication
RxFire was created by David East, who is a Firebase Developer Advocate. Although Firebase Blog introduced RxFire in September, 2018 I thought it would be a good point of reference for beginners starting out with both ReactJs and Firebase.
For those coming from an Angular background you might be familiar with RxJS and the Angularfire2 package. I know from my experience you MUST learn RxJS if you are going to use Angular on any size application. It can be one of the hardest parts to learn but there are several fantastic tutorials and sites dedicated to how RxJS works.
Some of my favorites
New to React, Please checkout
In the example below it shows a quick preview of how the final React application will work. As you can see there are essentiall 4 steps that will occur.
  1. Sign In
  2. Add Cat Fact
  3. Show Added Cat Fact in List
  4. Sign Out
You will need NPM which comes bundled with nodejs.
Since we wil be the create-react-app cli you must install this first https://facebook.github.io/create-react-app/docs/getting-started
You will also need to create your own Firebase project and initialize a Firestore database, please create this using strict mode.
Final App Structure
Loading image...
Install dependencies
You will need both rxfire and firebase
npm i rxfire firebase 
Create Firebase.js
Firebase.js will be our main Firebase file and will include the tools for our firebase application, including the instantiation of firebase. This file includes rxfire for both the auth and firestore helper functions.
import 'firebase/auth'; import 'firebase/firestore'; import firebase from 'firebase/app'; import { authState } from 'rxfire/auth'; import { collectionData } from 'rxfire/firestore'; import { filter } from 'rxjs/operators'; const app = firebase.initializeApp({ /* Place your configuration here */ }); const firestore = firebase.firestore(app); // Initialize firestore const auth = firebase.auth(app); // Initialize firebase auth const loggedIn$ = authState(auth).pipe(filter(user => !!user)); // Observable only return when user is logged in. export { app, auth, firestore, collectionData, loggedIn$ }; export default firebase; 
You can skip the Instructions part of the lesson if you are already familiar with ReactJS.
Simple Initial Component
Remove App.js and replace
Remove the core of App.js to start as we will be using the pattern of extends React.Component. We will now start simple by adding our first React Component Called Instructions.
import './App.css'; import React from 'react'; import Instructions from './components/Instructions'; class App extends React.Component { render() { return ( <div style={{ display: 'flex', justifyContent: 'center', flexFlow: 'row wrap' }} > <div style={{ display: 'flex', justifyContent: 'center', flexFlow: 'column' }} > <Instructions /> </div> </div> ); } } export default App; 
Create Instructions.js
This is a very simple React Component that takes no props, it just returns straight html.
import React from 'react'; class Instructions extends React.Component { render() { return ( <div style={{ display: 'flex', justifyContent: 'start', flexFlow: 'row wrap' }} > <div style={{ maxWidth: '500px' }} > <img src="https://res.cloudinary.com/ajonp/image/upload/q_auto/ajonp-ajonp-com/17-rxfire-react-cats/RxFire_3.webp" alt="rxfire for cats" width="100%" /> </div> <div> <p> In this example we will use RxFire to Observe the Cat Facts that we add to our Firestore Database. </p> <a href="https://github.com/AJONPLLC/rxfire-react-cats" target="no_index" > https://github.com/AJONPLLC/rxfire-react-cats </a> <ol> <li> Sign In <ul> <li>Uses Google Auth for Firebase</li> <li>Found in App.js</li> </ul> </li> <li> Add Cat Fact <ul> <li> This will use an API and Insert the facts into Firestore </li> <li>Found in components/AddCat.js</li> </ul> </li> <li> Firestore collection <ul> <li> Observing catfacts for changes, heart eyes are your facts </li> <li>Found in components/ListCatFacts.js</li> </ul> </li> <li> Sign Out <ul> <li>Observe that user is removed</li> </ul> </li> </ol> </div> </div> ); } } export default Instructions; 
Update collection catfacts
Create AddCat.js
The first button that we are going to add is simple enough it calls an API and pushes the data returned into a firestore collection as a new document. I always like to work from top down, so first lets import AddCat.js into our App.js.
Update App.js
... import AddCat from './components/AddCat'; ... <div style={{ maxWidth: '800px' }}> <AddCat /> </div> ... 
Now that it is in our App lets create the AddCat component. The only html that this passes back is onClick={this.addCatFact}. This is the JSX way of using onClick and passing a function. If you are new to ES6 arrow functions addCatFact = () => { is still just defining a function using a shortened syntax, it is becomming more standard these days.
The addCatFact function calls an API that returns a single random cat fact from https://cat-fact.herokuapp.com. Because of CORS we have to pass it through a proxy, but you will see that we get a value back. We then use the javascript destructuring assignment to create a new object by adding our catFactDate to the object. This allows us to later sort the facts in our list in descending order.
import React from 'react'; import { firestore } from '../Firebase'; class AddCat extends React.Component { addCatFact = () => { /* The dreaded CORS, had to pass through a proxy */ fetch( `https://cors-anywhere.herokuapp.com/https://cat-fact.herokuapp.com/facts/random?animal_type=cat&amount=1` ) .then(blob => blob.json()) .then(value => { console.log('fetched', value); firestore .collection('catfacts') .add({ ...value, catFactDate: new Date() }) .then( () => {}, reason => { alert('Must Be Logged In To Add, See Console'); console.log('Failed Adding Cat Fact', reason); } ); }); }; render() { return ( <button className="myButton" onClick={this.addCatFact}> 2. Add Cat Fact </button> ); } export default AddCat; 
Now if you try this right now it should fail with this alert Loading image...
This is expected as our firestore.rules are set to strict mode, we will add those after we get through our authentication section next.
You may also notice in the console (and on the screen fact jumps in and out) that firebase actually adds to our array, until failing on the backend. This is done on purpose as it gives us the fast UI that we expect while still maintaining the data integrity.
Add Firebase Authentication
Update App.js
We need to store using state within our application, so we can define a state object with a field user we will then use this from firebase when a user is logged in. We will also import a new SignIn button that we can use to hide show Sign In / Sign Out depending on the current state.
In the SignIn component we will for the first time start using props, we will pass the user state as well as a couple of our functions that are needed in the component to update our user.
 ... import { firestore, loggedIn$ } from './Firebase'; ... state = { user: null }; componentDidMount() { /* Observable from RxFire */ loggedIn$.subscribe(user => { this.authHandler({ user }); //Update state on load of app const { displayName, email, phoneNumber, photoURL } = user; firestore .collection('users') .doc(user.uid) .set({ displayName, email, phoneNumber, photoURL }); }); } authHandler = async authData => { this.setUser(authData.user); }; setUser = user => { this.setState({ user: user }); }; ... <Instructions /> <SignIn user={this.state.user} authHandler={this.authHandler} setUser={this.setUser} /> <div style={{ maxWidth: '800px' }}> <AddCat user={this.state.user} /> ... 
import React from 'react'; import firebase, { app } from '../Firebase'; class SignIn extends React.Component { signIn = () => { const authProvider = new firebase.auth.GoogleAuthProvider(); app .auth() .signInWithPopup(authProvider) .then(this.props.authHandler); }; signOut = async () => { await firebase.auth().signOut(); this.props.setUser(null); }; render() { if (!this.props.user) { return ( <button className="myButton" onClick={this.signIn}> 1. Sign In </button> ); } else { return ( <div> <span>Welcome {this.props.user.email} </span> <button className="myButton" onClick={this.signOut}> 4. Sign Out </button> </div> ); } } } export default SignIn; 
Update AddCat to include user uid
Pass user to AddCat
Update our main app to pass the user prop.
 <AddCat user={this.state.user} /> 
Now we can use this to include with our data going to firestore. AddCat.js
... .add({ ...value, uid: this.props.user.uid, catFactDate: new Date() }) ... 
As well as whether or not to show the Add Cat Fact button, we check to see if the user exists. This button should only show when a user is signed in.
 render() { let addCatButton = null; if (this.props.user) addCatButton = ( <button className="myButton" onClick={this.addCatFact}> 2. Add Cat Fact </button> ); return addCatButton; } 
Update firestore.rules
service cloud.firestore { match /databases/{database}/documents { // LockDown All match /{document=**} { allow read: if false; allow write: if false; } // User match /users/{userId} { allow read: if false; allow write: if request.resource.id == request.auth.uid; } // CatFacts match /catfacts/{catFactId} { allow read: if true; allow write: if request.auth.uid != null && request.resource.data.uid == request.auth.uid; } } } 
Create List of Cat Facts
Create ListCatFacts
This is probably the most important part of RxFire it will return an Observable that you can subscribe to for all changes to a collection by using the function collectionData which takes the collection as paramater as well as an option id to create, in our case we pass catFactsRef.orderBy('catFactDate', 'desc') and 'catFactId'.
Now we can just use a map to iterate on each catFact, whenever the Observable updates the current catFact state the array is updated and we can show the full list update using {this.state.catfacts.map(catFact => {.
import React from 'react'; import { collectionData, firestore } from '../Firebase'; class ListCatFacts extends React.Component { state = { catfacts: [] }; componentDidMount() { const catFactsRef = firestore.collection('catfacts'); collectionData( catFactsRef.orderBy('catFactDate', 'desc'), 'catFactId' ).subscribe(catfacts => { console.log('firestoreList', catfacts); // re-render on each change this.setState({ catfacts }); }); } componentWillUnmount() {} render() { return ( <> <h3>Firestore Collection "catfacts"</h3> {this.state.catfacts.map(catFact => { let myFact; if (this.props.user && this.props.user.uid === catFact.uid) { myFact = ( <span role="img" aria-label="fun-cat"> 😻 </span> ); } else { myFact = ( <span role="img" aria-label="fun-cat"> 😺 </span> ); } return ( <div key={catFact.catFactId}> {myFact} <span>{catFact.text}</span> </div> ); })} </> ); } } export default ListCatFacts;