JavaScript that writes JavaScript: Christoph will give an intro to jscodeshift and the underlying tools like recast and ast-types that help rewrite and modernize a lot of Facebook’s JavaScript code day-to-day. We’ll explore why these tools become increasingly important and how they change how we think about open source and breaking API changes at Facebook. At the end of the talk everyone will be able to run their own code transformations across all of their projects safely and efficiently.