Walmart uses a similar stack to the one we used at Alchemy. I'm backend, so I primarily write in NodeJS (although Hapi is the framework they use since they created it and open sourced). Some of the backend code bases are written in Java though. And front end uses React! Some of their tests are written in Jest (along with Mocha)-- Ryan did an excellent job teaching us, but there's no way you can learn everything in that amount of time (duh). What Ryan did was give us a SOLID foundation that we can build off of! Not gonna lie, sometimes it's overwhelming when you step back and think about how much you _don't_ know, but I still think Alchemy did an incredible job of preparing us for the tech world in just six short months!