webpack build errors out on "fs" and "child_process"

[Andrew Noblet]

webpack-dev-server --mode development works
webpack doesn't

dev-server was fixed by adding:

  externals: [
    {
      xmlhttprequest: "{XMLHttpRequest:XMLHttpRequest}"
    }
  ]

ouput is fine, but console displays errors?

[Andrew Noblet]

Serve and build work correctly. Build displays an error.