PS - This was orginally posted on my blog. Check it out if you want learn more about React and JavaScript!

tl;dr - Clone and run the source code.

Usually when starting to work on a React project, developers go with create-react-app. While this is a great option for many cases, I find it to be a bit too bloated, especially after ejecting it. I also find that it takes a little of work to manually setup and maintain a webpack config. Parcel is great for use with React as there is nothing to configure while setting up. It also helps that building the app in Parcel is also really fast.

First lets initialize a project with either yarn or npm. I'll be using yarn.

yarn init --yes

Then let's install Parcel as a dev dependency.

yarn add parcel-bundler -D

After that let's setup babel by installing the dev dependencies and creating the .babelrc file

yarn add @babel/core @babel/preset-env @babel/preset-react @babel/plugin-proposal-class-properties -D

Once the dependencies are done installing create the .babelrc file in the project root with the following code.

{
  "presets": ["@babel/preset-env", "@babel/preset-react"],
  "plugins": ["@babel/plugin-proposal-class-properties"]
}

This is all the setup we'll need to for Parcel to work with React. Now let's setup React.
First we'll need to the React dependencies.

yarn add react react-dom

If you want to use async/await in your code, an additional dependency is needed.

yarn add @babel/polyfill

Next we'll need an entry point for out app. The nice thing about Parcel is that the entry file doesn't have to be a JavaScript file. In our case its going to be a HTML file.
Create a folder with the name src. This folder is going to contain all the source code. In the src folder create the index.html file which is going to be the entry point of the app and add the follwing code.

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta
      name="viewport"
      content="minimum-scale=1, initial-scale=1, width=device-width, shrink-to-fit=no"
    />

    <title>React Parcel Starter</title>
  </head>
  <body>
    <div id="root"></div>
    <script src="index.js"></script>
  </body>
</html>

After that we'll create the index.js file (also in src) which will connect the root React component to the index.html file.

// src/index.js
import React from "react";
import ReactDOM from "react-dom";
import App from "./App.js";
import "@babel/polyfill";

ReactDOM.render(<App />, document.getElementById("root"));

Next let's create the root component in the App.js file.

// src/App.js
import React from "react";

const App = () => {
  return (
    <div>
      <h1>React Parcel Starter</h1>
    </div>
  );
};

export default App;

Finally all that's left to do is to add the scripts to run the app. Add the following in the package.json file.

"scripts": {
    "dev": "parcel ./src/index.html",
    "build": "parcel build ./src/index.html"
}

dev will be used to run the development of the app. Don't worry about restarting the server after making changes to the code while it's running, as Parcel will automatically take care of that. build is used to make the production version of the app in the dist folder in the project root.
Let's check if everything has been setup properly by running the dev command.

yarn dev

When you visit localhost:1234 in your browser you should be seeing

Now you can continue creating your React app as usual from here. The source code for everything done here is available in GitHub.

Getting started in React with Parcel.js