[Bug] Local development server broken

I’m noticing that fresh installs of React Static displays an empty page in develop mode ($ react-static start) and the console outputs SyntaxError: The URL 'http:/[http//localhost]:300' is invalid from SockJS. This occurs after running yarn upgrade in a previously working repo in either RS 6.3.x or 7.0.x. Seems that this is related to the 3.3.0 update of webpack-dev-server (possibly this change?).

Adding this to my project’s package.json and reinstalling dependencies fixes development builds. This confirms that something is borked in an update of webpack-dev-server.

"resolutions": {
  "react-static/webpack-dev-server": "~3.1.10"
}

Environment

  System:
    OS: macOS 10.14.4
    CPU: (4) x64 Intel(R) Core(TM) i5-6287U CPU @ 3.10GHz
    Memory: 228.44 MB / 16.00 GB
    Shell: 3.2.57 - /bin/bash
  Binaries:
    Node: 10.15.3 - /usr/local/bin/node
    Yarn: 1.15.2 - /usr/local/bin/yarn
    npm: 6.4.1 - /usr/local/bin/npm
  Browsers:
    Chrome: 73.0.3683.86
    Firefox: 66.0.2
    Safari: 12.1
  npmPackages:
    react-ga: ^2.5.7 => 2.5.7 
    react-markdown: ^4.0.6 => 4.0.6 
    react-moment: ^0.8.4 => 0.8.4 
    react-static: ^7.0.7 => 7.0.7 
    react-static-plugin-reach-router: ^7.0.0 => 7.0.0 
    react-static-plugin-sitemap: ^7.0.0 => 7.0.0 
    react-static-plugin-source-filesystem: ^7.0.0 => 7.0.0

Steps to Reproduce the problem

1. npx react-static create
2. create site and cd in
3. yarn upgrade to install latest dependencies
4. yarn start
5. navigate to http://localhost:3000
6. See broken site? Open console.

[J-F-Liu]

Find a workaround, add the following to packages.json, then yarn:

  "resolutions": {
    "react-static/webpack-dev-server": "3.2.1"
  }

[andrezero]

Same, still happens with 7.0.9, but this worked for me

  "resolutions": {
    "react-static/webpack-dev-server": "3.2.1"
  }