Create and showcase your own React UI library using Webpack 4

When working in a company with multiple projects, you might want to have design guidelines to ensure consistency throughout. What if you could have a showcase for your styled components and still be able to use those components in other projects, with something as easy as a installing a npm package?

March 17, 2018 - 5 minute read -

This tutorial shows how can one build a library of reusable components, showcase them and be able to easily import in other projects, using both Webpack 4 and Parcel bundler. Webpack will be responsible for handling the bundling of the library of components. Parcel bundler will handle the bundling of the show case of the components.

For this example, you will build a simple documentation showcase and a button as a shared component. All code is on

What you’ll be building

  • A library of UI components that can be used on other projects
  • A showcase for all the components of that library

Let’s get started. 🎉

Folder Structure

Let’s start by creating a folder structure. Firstly, let’s create a standard folder structure. The lib folder will contain the reusable React components and docs will contain the showcase for those components as well as any other documentation needed (such as the API for the components, for example).

At this point, the folder structure looks like this:

    |- docs
    |- lib
     |- index.js
     |- Button/
     |- index.js



This is everything you’ll need:

    // For showcasing our docs
    yarn add react react-dom

    // For bundling our library and docs
    yarn add webpack parcel-bundler webpack-cli webpack-node-externals "[email protected]^8.0.0-beta" @babel/core @babel/preset-env webpack-node-externals -D

lib/: react components library

Our library of React reusable components. When bundled (into /dist/lib) you’ll be able to consume them in another project by quickly installing this as a npm package, which could be public (where it’s possible to use the npm registry) or private (where gemfury could be used, for example). The index.js at the root of the lib folder will be responsible to export all the components of the library. For this case, you’ll be exporting a simple button only.

So our lib/index.js contains all the exported components by the library, (which will be a simple button for this case), so it will contain

    export { Button };

And in lib/Button/index.js , you’ll create and export a simple button. You could also have styling and it would still be bundled into one file.

    import React from 'react';
    const Button = ({ text }) => <button>{text}</button>;
    export { Button };  


docs/: documenting and showcasing the components

The docsfolder will showcase our library’s components as well as any other documentation needed (such as the API for the components, for example). It is just a small React application inside our main application. When bundled (into /dist/docs) it can easy be uploaded anywhere. Using the github pages would be a good cenario.

Now, you’ll create both and index.js and index.html, where the first one includes a component from the lib folder.

So, the index.js will contain

    import React from 'react';
    import ReactDOM from 'react-dom';
    import { Button } from '../lib/Button';

    const App = () => (
        <h1>My UI</h1>
        <p>Here's an example of button.</p>
        <Button text="Click me!" />

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

Nothing too fancy and the main gist is that it’s possible to see that there is a Button being imported from the library of components.


As mentioned, webpack is responsible to bundle the components library (and not the documentation). Let’s take a look at its configuration. The most important value here is the libraryTarget: ‘commonJS' which allows individual exporting of components.

    module.exports = {
      entry: path.resolve(__dirname, 'src/lib/index.js'),
      output: {
        path: path.resolve(__dirname, './build/lib'),
        filename: 'index.js',
        library: '',
        libraryTarget: 'commonjs'
      externals: [nodeExternals()],
      module: {
        rules: [
            test: /\.js$/,
            exclude: /(node_modules|bower_components)/,
            loader: 'babel-loader',
            options: {
              presets: ['@babel/preset-env', '@babel/react']
            test: /\.css$/,
            use: ['style-loader', 'css-loader']



The most important thing of the package.json is the “main”. After uploading the library to a registry (wether its npm or gemfury or other), this signals which file will be served as the entry point. The ./dist/lib/index.js contains all the code bundled from lib .


      "name": "myui",

      "version": "0.0.1",

      "description": "Bootstrapping a UI component library",

      "main": "./dist/lib/index.js",

      "scripts": {

      "start": "./node_modules/.bin/parcel src/docs/index.html",

      "build": "./node_modules/.bin/webpack --mode=production",

      "build:docs": "./node_modules/.bin/parcel build src/docs/index.js -d dist/docs/"


      "author": "Pedro Madruga",

      "license": "MIT",

      "dependencies": {

        "react": "^16.2.0",

        "react-dom": "^16.2.0"


      "peerDependencies": {

        "react": "^16.2.0",

        "react-dom": "^16.2.0"


       "devDependencies": {

       "@babel/core": "^7.0.0-beta.42",

       "@babel/preset-env": "^7.0.0-beta.42",

       "@babel/preset-react": "^7.0.0-beta.42",

       "babel-core": "6",

       "babel-loader": "^8.0.0-beta",

       "parcel-bundler": "^1.6.2",

       "webpack": "^4.1.1",

       "webpack-cli": "^2.0.12",

       "webpack-node-externals": "^1.6.0"




Importing from another project

Assuming your project is published somewhere (wether npm or gemfury), it will be easy as:

  `yarn add myUI`

and then in your file:

`import { Button } from ‘myUI’`

That’s it! Remember to check the repository for this example in