This session challenges the dominant trend of purely functional programming and immutable data that has influenced mainstream programming over the last decade. While functional programming brought predictability through pure functions and immutable data, it often comes with performance costs due to the need for data cloning, transformation, and diffing.

The talk explores how to achieve the best of both worlds by using controlled mutable state without sacrificing code clarity. Through practical examples, benchmarks, and real-world comparisons, attendees will learn techniques for encapsulating mutations effectively and discover client-server architectural patterns that can enhance performance while maintaining clean, declarative code.