This post is my take on displaying real-time views using Firebase and React. This has previously been done by Guillermo Rauch on rauchg.com and Lee Robinson on leerob.io.
Lee also explains how he did this in his blog.

So why should you read my post if they have already done so and even explained it? The reason being, both of the implementations require some sort of node environment to execute code while my post shows how you can achieve it on the client-side.

Another reason being, both websites are using Nextjs while mine is using Gatsbyjs and I couldn't find anything related to it. So here we are.

Setup

Setting up Firebase

Sign in to Firebase and go to console and create a new project. I'll name mine react-gatsby-views. You can enable Google Analytics if you want and click on create project

Navigate to Develop -> Database and click on "Create Database"
Choose "Start in Test Mode"

Choose your location and click on "Done"
Click on "Project Settings".

Click on web icon to create a "Web App"

Enter your name, I'll name mine react-gatsby-views-app do not enable Firebase hosting and click on "Register app"

Click on "Continue to console" as we'll need the config object later

Go to "Database" and select "Realtime Database"

Go to "Rules" and set read, write to true and click on "Publish" allowing us to update data without sigining in and using the config object

Setting up Gatsby

Create a Gatsby project by typing npx gatsby new enter_project_name in your terminal.
Go inside the created directory and install gatsby-firebase-plugin and firebase by typing npm install firebase gatsby-plugin-firebase in your terminal.
Register the Gatsby plugin by adding the below lines to your gatsby-config.js file

module.exports = {
  plugins: [
    ...otherPlugins,

    {
      resolve: 'gatsby-plugin-firebase',
      options: {
        credentials: {
          apiKey: '<YOUR_FIREBASE_API_KEY>',
          authDomain: '<YOUR_FIREBASE_AUTH_DOMAIN>',
          databaseURL: '<YOUR_FIREBASE_DATABASE_URL>',
          projectId: '<YOUR_FIREBASE_PROJECT_ID>',
          storageBucket: '<YOUR_FIREBASE_STORAGE_BUCKET>',
          messagingSenderId: '<YOUR_FIREBASE_MESSAGING_SENDER_ID>',
          appId: '<YOUR_FIREBASE_APP_ID>',
        },
      },
    },
  ],
};

you can refer the documentation here.

Since we are using Realtime Database, add import "firebase/database" to gatsby-browser.js and gatsby-ssr.js files.

// gatsby-browser.js and gatsby-ssr.js
import 'firebase/database';

Integration

Go to your Firbase console and select your web app.

Scroll down to Your apps and and copy the firebaseConfig object.

Create an .env file at the root of your project and paste the content like so

API_KEY='your_values_here'
AUTH_DOMAIN='your_values_here'
DATABASE_URL='your_values_here'
PROJECT_ID='your_values_here'
STORAGE_BUCKET='your_values_here'
MESSAGING_SENDER_ID='your_values_here'
APP_ID='your_values_here'
MEASUREMENT_ID='your_values_here'

Edit the gatsby-config.js file to consume the environment variables

    {
      resolve: 'gatsby-plugin-firebase',
      options: {
        credentials: {
          apiKey: process.env.API_KEY,
          authDomain: process.env.AUTH_DOMAIN,
          databaseURL: process.env.DATABASE_URL,
          projectId: process.env.PROJECT_ID,
          storageBucket: process.env.STORAGE_BUCKET,
          messagingSenderId: process.env.MESSAGING_SENDER_ID,
          appId: process.env.APP_ID,
        },
      },
    },

Install env-cmd as a dev dependency to use the environment variables by typing npm i -D env-cmd
Modify "develop" command in package.json to env-cmd -f .env gatsby develop
Add the below code to gatsby-config.js

require("dotenv").config({
  path: `.env.${process.env.NODE_ENV}`,
})
module.exports = {
  ...
}

Implementation

Go to src/pages/ and remove the unnecessary content with a simple one

// index.js
import React from 'react';
import ViewCounter from '../components/ViewCounter';

const Index = () => (
  <div>
    <ViewCounter id="index" />
  </div>
);

export default Index;

Don't worry if you get an error

we'll create the ViewCounter component in just a minute.

Create directory lib under src and a file named increment-views.js in it. It should look like this

src
 |-lib
    |-increment-views.js

Copy the below code into the file

// increment-views.js
import firebase from 'gatsby-plugin-firebase';

const incrementViews = async (id) => {
  const ref = firebase.database().ref(`/views`).child(id);

  ref.transaction((currentViews) => {
    return currentViews + 1;
  });
};

export default incrementViews;

This basically creates a reference of database to and creates an entry of id under views. Different ids will create additional entries and will update the view whenever the function is called.

ref.transaction() is used to modify the data at the location. In our case views of id are incremented.

Create a file ViewCounter.js under src/components/ and copy the below code

// ViewCounter.js
import React, { useEffect, useState } from 'react';
import firebase from 'gatsby-plugin-firebase';
import incrementViews from '../lib/increment-views';

const ViewCounter = ({ id }) => {
  const [viewCount, setViewCount] = useState('');

  useEffect(() => {
    // 1 is displayed for a split second and then the correct count
    // This is a workaround
    const onViews = (newViews) => {
      setViewCount(newViews.val() === 1 ? 0 : newViews.val());
    };

    incrementViews(id);

    firebase.database().ref(`/views`).child(id).on(`value`, onViews);

    return () => {
      if (firebase.database()) {
        firebase.database().ref(`/views`).child(id).off(`value`, onViews);
      }
    };
  }, [id]);

  return (
    <div style={{ color: '#7e7e7e' }}>
      {viewCount ? viewCount : `---`} views
    </div>
  );
};

export default ViewCounter;

On loading this component, id is sent to increment-views to increment the value and the returned value is stored in viewCount.

Upon completion, if an instance of database exists, detach it using off()

Now everytime you refresh the page or anyone visits it, view count will be incremented

App Views

Firebase Views

Deployment

Since I have deployed my site on Zeit, it uses now secrets. Each host provider has a different mechanism to handle environment variables.

I hope you've liked this post. Any suggestions, improvements are welcome.

Displaying Real-Time Views using React, Gatsby and Firebase