Hi there, just writing up a quick issue for the benefit of any other people who might like to try this tutorial.
It seems any version of @babel newer than v7.13.8 no longer works correctly in this tutorial (I think we're up to v7.17.0 now).
After many hours of problem solving I finally found a thread which explains the version problem here at parcel-bundler/parcel#5943.
If you do try to use this Tutorial, I strongly urge you to clean your NPM Cache directory. It seems that if you've previously loaded a version of @babel in another project, the newer version in your cache gets loaded into THIS tutorial in your node-modules folder.
And then everything dies when you try to run "npm start".