The instructor introduces Babel in one of the sections, and has us install the Babel command line tool.
Using npm, you should be able to install it like so:
npm install -g email@example.com
When I tried this, I got an “EACCES: permission denied” error.
You can try following the instructions here to fix it for you. A lot of people in the course had success with this.
I don’t know what I did to my MacBook, but the suggestions above STILL did not fix it for me.
After scouring Stack Overflow and Google, the only way I could get the Babel CLI to work was to recursively update the permissions of the .npm folder in my home directory:
sudo chown -R $(whoami) ~/.npm
I hope this helps somebody!