I've spent a lot of time debugging and doing performance optimization investigations throughout my career. It's second nature to me at this point, but a lot of developers have never really tried to investigate app performance.
In late 2025 I spent multiple months investigating and optimizing performance in the Immer immutable update library.
This talk covers how to approach performance investigation with a scientific approach mindset. It covers key investigation approach concepts, common perf profiling and visualization tools, and techniques to optimize code to run faster, and uses experiences from my Immer work as practical examples.