# Reactivity and signals: demystifying frontend magic

> Unpack frontend reactivity: change propagation, dependency tracking, signals, computed values, and effects in modern frameworks.

- Date: 2025-11-13
- Event: [DevFest Toulouse](<https://devfesttoulouse.fr/>)
- Location: Toulouse, France
- Topics: computed-values, dependency-tracking, effects, frontend-reactivity, signals, vue

## Resources

- [Slides](<https://talks.soubiran.dev/2025-11-13/devfest-toulouse>)
- [PDF](<https://talks.soubiran.dev/2025-11-13/devfest-toulouse/pdf>)
- [Source code](<https://talks.soubiran.dev/2025-11-13/devfest-toulouse/src>)

## Summary

Frontend frameworks hide a dependency-tracking system behind their reactive APIs. This talk makes that system visible with `alien-signals`, showing how signals, computed values, and effects form a graph that can be updated when state changes.

The examples use directed graphs, topological ordering, doubly linked lists, and push-pull propagation to explain the underlying algorithms. They finish by comparing this model with Vue's component-level reactive effects.