Ever feel like JavaScript’s event loop is a black box? Or that you’re just "hacking" your way through Promises until they work?
Understanding that JS doesn't actually have a concept of "time"—only a queue of events.
Beyond just "fast code"—thinking about Web Workers, SIMD, and benchmarks that actually matter.
The secret sauce for making async code look and behave like synchronous code (the foundation of async/await ).