Reactivity and signals: demystifying frontend magic

How does a frontend know which code to run after state changes? This talk answers the question with ui = fn(state), an Excel example, and a small reactive system built with alien-signals.

It introduces dependency graphs and doubly linked lists, then explores subscribers, computed values, effects, propagation strategies, and several unresolved problems such as glitches, cycles, mutable state, and changing dependency graphs. The last examples show how these mechanisms map to Vue.