Navigating large-scale changes in a codebase can be daunting—hundreds of files, numerous breaking changes, and the ever-present risk of human error. But what if you could automate this process and transform it from a nightmare into a seamless operation?

In this session, we'll dive into the world of codemods and Abstract Syntax Trees (ASTs), powerful techniques that enable precise and efficient code transformations. Through a compelling real-world case study, I'll showcase how we tackled a major version upgrade involving 70 breaking API changes in a large React project—and completed the migration in just 3 whopping minutes (!), but the benefits of codemods extend beyond major upgrades. They can revolutionize your day-to-day development by automating repetitive tasks and ensuring code consistency at scale. By the end of this talk, you'll walk away with practical insights and tools to integrate codemods into your workflow, making large-scale changes faster, safer, and more reliable.