# Reactivity and signals: demystifying frontend magic

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

- Date: 2025-10-14
- Event: [Paris TypeScript](<https://typescript.paris/>)
- Location: Paris, France
- Topics: computed-values, dependency-tracking, effects, frontend-reactivity, signals, vue

## Resources

- [Slides](<https://talks.soubiran.dev/2025-10-14/paris-typescript>)
- [PDF](<https://talks.soubiran.dev/2025-10-14/paris-typescript/pdf>)
- [Source code](<https://talks.soubiran.dev/2025-10-14/paris-typescript/src>)

## Summary

This talk explains frontend reactivity through dependency graphs, signals, computed values, and effects. It uses `alien-signals` to show how a change in a signal reaches the computations and effects that depend on it.

The examples cover graph traversal, doubly linked lists, push and pull propagation, and the implementation of signal getters, computed values, and effects. The final section relates this low-level model to Vue's component update mechanism.