Fixing Jest on macOS 10.15.2

Sorting out all of the different JavaScript frameworks can be a chore

Most of the JavaScript frameworks and tools are under constant change. Staying on top of all of the churn can be a chore. I recently came across an issue after I upgraded to the latest version of macOS (10.15.2), Xcode (11.2) and Node.js 13.0.1. None of my Jest based tests would run anymore. When I ran npm test or yarn test jest would start, but would never run any tests. It was like jest was just hanging or stuck, and not able to run any of the tests.

I tried reinstalling Node.js, downgrading Node. I even emptied the NPM cache and reinstalled jest. Nothing I did worked. I came across a Stackoverflow post. One of the tools Jest uses is called watchman. The Stackover flow post suggested uninstalling and reinstalling watchman. You can use Homebrew to do this on the Mac. If you are not familiar with Homebrew, it is essentially the missing package manager for macOS.

brew uninstall watchman
brew install watchman

After I made this change, I reinstalled jest onto my computer, and now all of my tests run like they did before. I hope this helps with your set up as well.