Let’s assume your directory structure looks like this for a JavaScript project:

.
├── config/
│   └── webpack.config.js
├── dist/
├── node_modules/
├── src
│   ├── components/
│   ├── util/
│   └── index.js
├── package.json
├── yarn.lock
├── index.html

And all you want is a simple webpack config that creates a single bundled JavaScript file.

First, install webpack if you haven’t already done so:

yarn add webpack webpack-cli

Once that’s done, add this script to your package.json:

package.json
"scripts": {
    "build": "webpack --config config/webpack.config.js --mode production"
}

And then create this simple webpack config under config/:

webpack.config.js
const path = require('path');

module.exports = {
  context: path.resolve('src/'),
  // Start here: /src/app.js
  entry: {
    main: path.resolve(__dirname, '../src/index.js'),
  },
  // Put the bundled code here: /dist/app.bundle.js
  output: {
    path: path.resolve(__dirname, '../dist/'),
    filename: 'app.bundle.js',
  },
};

Here’s how it works:

  1. entry tells webpack where to look for your app’s entry point. In this case, that’s index.js. Note that it expects an absolute path to the file, hence why we need path.resolve.

  2. output tells webpack where to put the bundled JavaScript. In this case, we’ll put it under dist/app.bundle.js. Note that the dist/ directory must exist; it won’t get created for you.

Run yarn build to bundle your code. Here’s some sample output:

yarn run v1.22.4
$ webpack --config config/webpack.config.js --mode production
Hash: d60fd368c37fd04c102f
Version: webpack 4.43.0
Time: 209ms
Built at: 07/01/2020 7:59:18 AM
        Asset      Size  Chunks             Chunk Names
app.bundle.js  1.08 KiB       0  [emitted]  main
Entrypoint main = app.bundle.js
[0] ./index.js + 3 modules 499 bytes {0} [built]
    | ./index.js 188 bytes [built]
    | ./util/log.js 70 bytes [built]
    |     + 2 hidden modules
Done in 2.47s.

Now you can include the bundled code in your HTML file:

index.html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>A Simple Webpack Config</title>
</head>
<body>    
    <script src="dist/app.bundle.js"></script>
</body>
</html>

And that’s all you need for a simple webpack config!

Webpack Absolute Imports

Relative imports can get pretty nasty: import X from '../../../'.

To use absolute imports in webpack, we’ll set up import aliases. Here’s the new webpack config:

config/webpack.config.js
const path = require('path');

module.exports = {
  resolve: {
    alias: {
      components: path.resolve(__dirname, '../src/components'),
      util: path.resolve(__dirname, '../src/util'),
    },
  },
  entry: {
    main: path.resolve(__dirname, '../src/index.js'),
  },
  output: {
    path: path.resolve(__dirname, '../dist/'),
    filename: 'app.bundle.js',
  },
};

So imports like this:

import Module from '../../components/Module';

Become this:

import Module from 'components/Module';

If you’re using VS Code, you can take this one step further and create a jsconfig.json:

jsconfig.json
{
    "compilerOptions": {
        "baseUrl": "./src/",
        "paths": {
            "components/*": ["components/*"],
            "util/*": ["util/*"],
        }
    }
}

So now, if you start typing the name of a non-imported module, VS Code will look it up and automatically import it for you.

Auto-importing modules in VS Code

I hope this helps!