Step By Step React Configuration

Posted on January 07, 2019


Learn to Setup your React app from scratch using webpack and Babel.

So you've been using create-react-app a.k.a CRA for a while now. It's great and you can get straight to coding. But when do you need to eject from create-react-app and start configuring your own React application? There will be a time when we have to let go of the safety check and start venturing out on our own. This guide will cover the most simple React configuration that I personally used for almost all of my React projects. By the end of this tutorial we will have our own personal boilerplate and learn some configurations from it.

Why create your own configuration?

There are certain reasons that make creating your own React configuration make sense. Obviously, you are good with React and you want to learn how to use tools like webpack and Babel on your own. These build tools are powerful, and if you have some extra time, it's always good to learn about them. Developers are naturally curious people, so if you feel you'd like to know how things work and which part does what, then let me help you with it. Furthermore, hiding React configuration by create-react-app is meant for developers starting to learn React, as configuration should not stand in the way of getting started. But when things get serious, of course you need more tools to integrate in your project. Think about:

  • Adding webpack loaders for less, sass
  • Doing server side rendering
  • Using new ES versions
  • Adding MobX and Redux
  • Making your own configuration just for learning sake

If you look around the Internet, there are some hacks to get around CRA limitations like create-react-app rewired. But really, why not just learn React configuration on your own? I will help you get there. Step by step.

Now that you're convinced to learn some configuration, let's start by initializing a React project from scratch.

Open up the command line or Git bash and create a new directory

mkdir react-config-tutorial && cd react-config-tutorial

Initialize NPM project by running:

npm init -y

Now install react

npm install react react-dom

Also, you can view the source code on GitHub while reading this tutorial for explanations about the setting.

Configuring webpack 4

Our first stop will be the webpack. It's a very popular and powerful tool for configuring not only React, but almost all front-end projects. The core function of webpack is that it takes a bunch of JavaScript files we write in our project and turns them into a single, minified file, so that it will be quick to serve. Starting from webpack 4, we aren't required to write a configuration file at all to use it, but in this tutorial we will write one so that we can understand it better.

First, let's do some installation

npm install --save-dev webpack webpack-dev-server webpack-cli

This will install:

  • webpack module — which include all core webpack functionality
  • webpack-dev-server — this development server automatically rerun webpack when our file is changed
  • webpack-cli — enable running webpack from the command line

Let's try to run webpack by adding the following script to package.json

"scripts": {
  "start": "webpack-dev-server --mode development",
},

Now create an index.html file in your root project with the following content:

<!DOCTYPE html>
<html>
  <head>
    <title>My React Configuration Setup</title>
  </head>
  <body>
    <div id="app"></div>
    <script src="./dist/bundle.js"></script>
  </body>
</html>

Create a new directory named src and inside it, create a new index.js file

mkdir src && cd src && touch index.js

Then write a React component into the file:

import React from "react";
import ReactDOM from "react-dom";

class Welcome extends React.Component {
  render() {
    return <h1>Hello World from React boilerplate</h1>;
  }
}

ReactDOM.render(<Welcome />, document.getElementById('root'));

Run the webpack by using npm run start ... And an error will be triggered.

You may need an appropriate loader to handle this file type

Configuring Babel 7

The React component we wrote above used the class syntax, which is a feature of ES6. Webpack needs Babel to process ES6 into ES5 syntaxes in order for this class to work.

Let's install Babel into our project

npm install --save-dev @babel/core @babel/preset-env \
@babel/preset-react babel-loader

Why we need these packages?

  • @babel/core is the main dependency that include babel transform script
  • @babel/preset-env is the default Babel preset used to transform ES6+ into valid ES5 code. Optionally configure browser polyfills automatically
  • @babel/preset-react is used for transforming JSX and React class syntax into valid JavaScript code
  • babel-loader is a webpack loader that hook Babel into webpack. We will run Babel from webpack with this package

To hook Babel into our webpack, we need to create a webpack configuration file. Let's write a webpack.config.js file:

module.exports = {
  entry: './src/index.js',
  output: {
    path: __dirname + '/dist',
    publicPath: '/',
    filename: 'bundle.js'
  },
  devServer: {
    contentBase: './',
    publicPath: '/dist/'
  },
  module: {
    rules: [
      {
        test: /\.(js|jsx)$/,
        exclude: /node_modules/,
        use: ['babel-loader']
      }
    ]
  },
};

This webpack config is basically saying that the entry point of our application is from index.js, so pull everything that's needed by that file, then put the output of the bundling process into the dist directory, named bundle.js. Oh, if we're running on webpack-dev-server, then Tell the server to serve content from contentBase config, which is the same directory this config is in. For all .js or .jsx files, use babel-loader to transpile all of them.

In order to use Babel presets, create a new .babelrc file

touch .babelrc

Write the following content:

{
  "presets": [
    "@babel/preset-env",
    "@babel/preset-react"
  ]
}

Now run npm run start again. This time it will work.

Adding Prettier

To further speed up development, let's make our code formatter using Prettier. Install the dependency locally and use the --save-exact argument since Prettier introduce stylistic changes in patch releases.

npm install --save-dev --save-exact prettier

Now we need to write the .prettierrc configuration file:

{
  "semi": true,
  "singleQuote": true,
  "trailingComma": "es5"
}

The rules means that we want to add semicolon for the end of every statement, use a single quote whenever appropriate and put trailing commas for multi-line ES5 code like object or array.

You can run Prettier from the command line with:

npx prettier --write "src/**/*.js"

Or add a new script to our package.json file:

"scripts": {
  "test": "echo \"Error: no test specified\" && exit 1",
  "start": "webpack-dev-server --open --mode development",
  "format": "prettier --write \"src/**/*.js\""
},

Now we can run Prettier using npm run format

Additionally, if you're using VSCode for development, you can install Prettier extension and run it every time you save your changes by adding this setting:

"editor.formatOnSave": false

Conclusion

You've just created your very own React project boilerplate. Congratulations! Granted, I didn't go very deep on webpack configurations, because this boilerplate is meant to be a generic starter. In some cases where we need advanced features like server side rendering, we need to tweak the configuration again. But don't worry! You've come this far, which means you already understand what webpack, Babel and even Prettier do. You'll learn more about configuration as your project increase in complexity.

Want to learn more?

I'm giving away free PDF version of this guide which includes:

  • adding source map for better error logging
  • setting up ESLint
  • adding css processors such as LESS
  • deploying your React app to netlify

Thanks for reading and I hope you learned something from this post :)

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