Presenter: Joey Watts @joeywatts96

The TypeScript compiler is a complex piece of software. It’s capable of reasoning through a Turing-complete type system and making new JavaScript features run in old browsers. What is it like to work on the TypeScript compiler? In this talk, you’ll learn about how the compiler is structured and the process of implementing a large feature in the compiler, based on my experience contributing to the ES private fields implementation that shipped in TypeScript 3.8. Along the way, you’ll also gain familiarity with ES private fields, how they interact with existing TypeScript features, and what they mean for TypeScript developers. After this talk, hacking around in the compiler codebase hopefully won’t feel so daunting!