✨ Creating A React App

Photo by Rolands Zilvinskis on Unsplash

This is part 2 of my series on server-side rendering (SSR):

  1. 🤷🏻‍♂️ What is server-side rendering (SSR)?
  2. [You are here] ✨ Creating A React App
  3. 🎨 Architecting a privacy-aware render server
  4. 🏗 Creating An Express Server
  5. 🖥 Our first server-side render
  6. 🖍 Combining React Client and Render Server for SSR
  7. ⚡️ Static Router, Static Assets, Serving A Server-side Rendered Site
  8. 💧 Hydration and Server-side Rendering
  9. 🦟 Debugging and fixing hydration issues
  10. 🛑 React Hydration Error Indicator
  11. 🧑🏾‍🎨 Render Gateway: A Multi-use Render Server

Last week, I gave my own brief history of web sites and how their frontend implementation has drifted from entirely server-based, to entirely client-based, and is now settling (perhaps) with hybrid that we call server-side rendering (SSR). The goal of this journey is to poke around the gnarly bones of SSR and learn what we learn. We may make mistakes, break idioms, and portray ourselves as fools, but we will definitely learn. For that reason, we are not going to bother with things like Next.js, which have already fleshed over and hidden away the gnarly bones for us1.

Now, before we dip even further in the specific world of SSR, we are going to need an app. To be specific, we are going to need a React app.

Hello, React World!

Before creating a React app, we need a package manager; either npm or yarn will suffice. Though we could put together our own app from scratch, there is no need to as the handy create-react-app package exists. There are numerous ways to use this, but the easiest is to use yarn create or npx, which will do the work of obtaining the package and executing it all in one go.

For yarn, drop create from the front of create-react-app:

yarn create react-app <app-name-here>

For npx:

npx create-react-app <app-name-here>

I want to also put this in a git repository so I can track my changes. I would normally make a directory, run git init and then get started. In this case, we do not need to as create-react-app takes care of that for us.

So, let's begin. Open a terminal and invoke create-react-app.

yarn create react-app hello-react-world

After executing this, you will have a working React app that uses react-scripts to manage the basics. This is perfect for our initial journey. If we navigate to that directory and run the project, we can see our app in action.

cd hello-react-world
yarn start
Screenshot of the website created by the create-react-app tool. It shows the React logo in blue, over a dark grey background, with the text "Edit src/App.js and save to reload." and a link labelled, "Learn React"

Fantastic. We have an app. Before we do any more, let's get some remote source control underway. I am paranoid of my machine dying and losing all my work, so having an off machine place to store things is really useful. First, add a new repository on your source control site of choice (I prefer GitHub). Second, connect the local repository to the remote one:

git remote add origin <repo-url>
git fetch
git branch --set-upstream-to origin/master master

Since we want our local code to be the first commit and we're pushing to a brand new repository, we can force push what we have.

git push -f

Routing

Okay, we have an app and it is in source control. This is usually a good spot to spend some time setting up code quality tools like eslint and prettier. I am going to be naughty and skip right over that right now and save it for a different post, perhaps. Instead, let us add some routing to our fledgling application.

There are a few options for implementing routing in a React application (some frameworks, like Next.js, even provide it out of the box). We are going to use React Router. There are two variants of React Router; one for React on websites, and one for React Native on mobile. We want the website variant, which is provided by the react-router-dom package.

yarn add react-router-dom

Now we will edit our app to have a couple of routes. The main app is defined in the src/App.js file. It should look something like this. I have highlighted the lines we're going to replace; we are also going to add some too.

import React from 'react';
import logo from './logo.svg';
import './App.css';

function App() {
  return (
    <div className="App">
      <header className="App-header">
        <img src={logo} className="App-logo" alt="logo" />
        <p>
          Edit <code>src/App.js</code> and save to reload.
        </p>
        <a
          className="App-link"
          href="https://reactjs.org"
          target="_blank"
          rel="noopener noreferrer"
        >
          Learn React
        </a>
      </header>
    </div>
  );
}

export default App;

There are two things we want to add.

  1. The routes to render our pages.
  2. The links to navigate to our routes.

First we import four things from react-router-dom:

  1. BrowserRouter
    This is the root of our React Router-based navigation. Basically, the router is responsible for the routing (I'm sure you guessed that).
  2. Link
    This replaces the anchor tag (<a>) for our navigation.
  3. Route
    This is used to render a matched route.
  4. Switch
    This allows us to specify a table of possible routes that can be used to work out what should handle the URL currently being viewed.

With these things, we can then add some routes. I am adding Home, About, and Contact. Here is my app code after the edit. I have highlighted the new lines.

import React from 'react';
import {BrowserRouter, Link, Route, Switch} from "react-router-dom";
import logo from './logo.svg';
import './App.css';

function App() {
  return (
    <BrowserRouter>
      <div className="App">
        <header className="App-header">
          <img src={logo} className="App-logo" alt="logo" />
          <div className="App-links">
            <Link className="App-link" to="/">Home</Link>
            <Link className="App-link" to="/about">About</Link>
            <Link className="App-link" to="/contact">Contact</Link>
          </div>
        </header>
        <section className="App-content">
          <Switch>
            <Route path="/about">
              This is the about page!
            </Route>
            <Route path="/contact">
              This is the contact page!
            </Route>
            <Route path="/">
              This is the home page!
            </Route>
          </Switch>
        </section>
      </div>
    </BrowserRouter>
  );
}

export default App;
Screenshot of the updated app using React router. The top shows the React logo with three links below it for "Home", "About" and "Contact" all on a dark grey background. Below that is a white region with the text "This is the home page!"

I also edited the CSS a little, but only to make things easier to see. The important bits are the router, wrapping our app, the Link components to perform navigation, and the Route components that render each route. With this, we now have a single page React app that has three pages for home, about, and contact.

This is going to be the application we will eventually render on the server. The important take away at this point is that we are not going to change the functionality of this app in order to achieve our aim. There are some changes we must make to support SSR, but we will not have two versions of the code. The code that runs in the browser will run on the server.

Next time, we are going to setup a server that will perform our SSR and consider what changes we need to make to our application infrastructure in order to support it. We might even get our first server-side rendered page. Until then, thanks for joining me on this continued exploration of server-side rendering using React.

  1. of course, if starting a new project knowing you need SSR, you should explore solutions like Next.js []

🤷🏻‍♂️ What is server-side rendering (SSR)?

Featured image modified from photo by Andre Mouton on Unsplash

This is part 1 of my series on server-side rendering (SSR):

  1. [You are here] 🤷🏻‍♂️ What is server-side rendering (SSR)?
  2. ✨ Creating A React App
  3. 🎨 Architecting a privacy-aware render server
  4. 🏗 Creating An Express Server
  5. 🖥 Our first server-side render
  6. 🖍 Combining React Client and Render Server for SSR
  7. ⚡️ Static Router, Static Assets, Serving A Server-side Rendered Site
  8. 💧 Hydration and Server-side Rendering
  9. 🦟 Debugging and fixing hydration issues
  10. 🛑 React Hydration Error Indicator
  11. 🧑🏾‍🎨 Render Gateway: A Multi-use Render Server

One of my main responsibilities at work involves server-side rendering (SSR). From managing the services that perform SSR to the client components that developers use to build SSR-able frontends, I have my focus on many pieces of our frontend infrastructure. In this series of posts, I want to share some of the things I have learned and perhaps demystify this mostly fantastic approach to creating performant, stable, web experiences.

When the Internet started coming alive the first time, a lot of the magic was implemented on servers (aka server-side or "on the backend") that built HTML pages to deliver to web browsers. During this period, impressive collections of user interface components were created to make developing these server-based web apps easier and more reliable. Sadly, sites often felt a clunky and slow because the browser just was not equipped to do much beyond rendering the HTML it was given; JavaScript execution was too slow for anything very meaningful. Even button clicks in the browser would cause a new request to the server that would then generate a whole new page for the browser.

Then Google Chrome and the v8 JavaScript engine came along and changed everything. Browsers became blessed with speedy JavaScript engines. That meant we could do a lot of this work in the browser (aka client-side or "on the frontend") and develop applications that could properly divide presentation (the application running in the browser) from data (the database and CRUD1 operations running in the backend). From this new power came the concept of the single page app (SPA), where one page comes from the server and then does most of its work client-side, deferring to the backend only when data is read or written. Often, the page is received from the server in an initial state and then subsequent data requests may populate that page (imagine your Facebook feed loading) to get it ready for you to use. However, this can mean that the time to interactive – the length of time before a user can actually use the page – is long. This affects all sorts of things, but particularly user retention. Folks don't like waiting and if they wait too long, they become frustrated and eventually bounce2.

Much like in the backend era prior to faster frontend JavaScript execution, new frameworks and user interface components have appeared that help to create powerful web apps using browser-based JavaScript. Things like Angular, Ember, and React (there are more – there are always more3). However, there can still be a mismatch between backend and frontend. To get a nice experience for our users, code runs on the backend to build an initial page and then that is handed to the frontend, which promptly takes over. Sometimes, this transition is nice and smooth, but other times it is not. More importantly, there are at least two different code paths for generating the page; at least one backend one and at least one frontend one4.

Having more than one code path trying to do equivalent work is hard to maintain. A change in one place may or may not need a change in the other, and either way, careful quality engineering is needed to make sure bugs are not introduced. The shift away from web apps executing entirely on the backend but rendered on the frontend to being executed mostly on the frontend with a bit of backend increased the complexity of the code for anyone that wanted a performant, engaging web site. You had a choice; either keep the separation of frontend for presentation and backend for data, and have a slower initial website experience, or blur the line and have more complex code, but a nicer user experience. Thankfully, folks thought about this and like those responsible for React, came up with a solution – server-side rendering (SSR).

Thanks to the JavaScript Revolution that started with v8, we now are able to run JavaScript outside of our web browsers (using NodeJS, for example). This creates some interesting opportunities for running the same code in both the frontend and backend. This does not mean that all the code would run in two places – we may want to keep the CRUD operations as a backend thing; however, being able to run our presentation code in both places means we can overcome some of that delay when a user first visits a page of our site. We can use the same JavaScript that would render our page in the web browser to render a version of our page on the server and then let the browser take over, all with a single codebase5.

Server-side rendering (SSR) – The rendering of a web page on a server rather than in a browser

And in the context of what I want to write about, that is server-side rendering (more commonly referred to as SSR, at least by me, anyway) – the rendering of a web page on a server rather than in a browser. In fact, it's so similar to rendering in a web browser, I have started to refer to the server responsible for SSR as a server-side browser. This tends to reframe how folks think of problems they face and how to start thinking about frontend code not as "does this run in the server or the client?" but "what browsers does this have to support?". It turns out that second question is much more familiar to most frontend developers than the first.

For now, I will leave things there. I think this post is quite long enough. Thank you for reading. Over the next few posts, we will look at creating an app using React that supports SSR, as well as a backend browser to perform that SSR, and the implications that SSR has when it comes to writing frontend code.

  1. Create Read Update Delete []
  2. there's a reason it's called "bounce rate" []
  3. While I was writing this, I expect three more frontend frameworks came into being and at least one died []
  4. There are cases where different parts of the same page are rendered by different services; front or backend – talk about complicated []
  5. Not only that, but the server response could be cached with a CDN (content delivery network) to make our sites even faster! []