I think I found the answer

Tools -> Create command line launcher

You’ll be asked to add /Applications/WebStorm.app/Contents/MacOS to your $PATH

Then you can

cd /path/to/project
webstorm .

Worked for me at least.

Credit goes to LazyOne on StackOverflow

In the settings it says "Prettier package not specified. But I’m using the “Automatic prettier configuration” option and it works perfectly when triggered manually through the contextual menu (right clicking).