Access local webpack dev servers from external devices

Sometimes we would like to access a local development server externally. It happens when we want to see how our web application works on mobile phones. Or co-workers want to see how it looks on their browsers.
The local server is available at `http://localhost:PORT` where `PORT` represents the port number that the server listens on. In order to make it accessible in the same network, we have to replace `localhost` with the IP address.
Webpack dev server allows the server to be available externally via the `host` option:
// webpack.config.js
module.exports = {
devServer: {
host: '',
port: 8001,
The `host` option can be passed to the command line interface as well:
webpack serve --host
With the configurations above, we can access the server internally (`http://localhost:8001`) and externally (`http://THE-IP-ADDRESS:8001`).