Despite its recent resurgence in the frontend ecosystem, the concept of fine grained reactivity has existed in JavaScript for at least 15 years. But they have never been as prominent as they are today, with every major frontend framework (and most state managers) investing significant effort into making themselves fine grained. There’s even a proposal to add it into the JavaScript language. But how exactly did this happen, and why now?

This session will explore the history of Signals and fine grained reactivity, and how they evolved from a niche approach used by a single library to a unanimously agreed on standard. We will compare fine grained reactivity to competing approaches, discuss trade-offs, and explore some ongoing research into next generation capabilities fueled by signals.