dev:wds error on chapter 4

Created by: pzac

Type of issue: (feature suggestion, bug?)

Bug

Chapter:

4 - HMR

If it's a bug:

yarn dev:wds was triggering an error

url.js:576
    host = auth + (this.hostname.indexOf(':') === -1 ?
                                 ^
TypeError: this.hostname.indexOf is not a function

The error persisted until I added the host flag to the dev:wds script in package.json:

"dev:wds": "webpack-dev-server --progress --host 0.0.0.0",