Reactivity and signals: demystifying frontend magic

Reactive rendering depends on knowing which computations use which pieces of state. This talk explores that relationship with alien-signals, from the basic signal, computed, and effect APIs to the data structures used to track dependencies.

It explains how updates propagate, why reactive systems need to deal with cycles and mutable state, and how a small signal-based framework can update the DOM. The final example connects the same ideas to Vue's ReactiveEffect.