# BlaC Documentation — DirtyTalk

Type-safe state management for React with automatic re-render optimization. Comprehensive guide covering core concepts, React integration, plugins, testing, and framework integrations.

This file contains the full text of the DirtyTalk documentation only. See /llms.txt for the complete index.

---

# DirtyTalk

> The framework-agnostic packages under BlaC — after a mutation, what changed, who cares, and when do we tell them?

Source: /dirtytalk/

DirtyTalk is the family of packages BlaC is built on. They answer one question: **after a mutation, what changed, who cares, and when do we tell them?**

You do not need to install or import these to use BlaC — `@blac/core` wires them up for you. This page exists so the layering is on record.

## The idea

A renderer mutates a scene and must repaint. A state container mutates state and must notify subscribers. Both face the same three questions, and the naive answer pushes the work down to every consumer — re-walking the whole state tree once per subscriber, or repainting the whole canvas because a single dirty bit lost track of _where_ the change was.

DirtyTalk computes "what changed" **once, at the source**, as a **Region** — a value with `empty`, `union`, and `intersects`. Each subscriber declares an interest region. Waking the right subscribers is then one cheap `intersects` check each, against one shared dirty region: work proportional to the number of subscribers, not to the size of the state times the number of subscribers.

## The packages

| Package                 | Role                                                                                                                                              | A `Region` is              |
| ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------- |
| `@dirtytalk/engine`     | The abstract algebra and scheduling glue: the `Space<Region>` and `Scheduler` interfaces, and `DirtyChannel<Region>`. Ships no concrete `Region`. | abstract — you supply one  |
| `@dirtytalk/spatial`    | The 2D-rendering instantiation. `RectSpace`, a `SceneNode` / `SceneRoot` tree, and a `PointerRouter`.                                             | a list of damage rects     |
| `@dirtytalk/structural` | The state-container instantiation. `PathSetSpace`, a `PathInterner`, the `trackRender` proxy recorder, and diff helpers.                          | a set of interned path IDs |

Each domain package answers the same algebra in its own terms. "Union two dirty regions" means concatenating damage lists in spatial and set-union in structural. The `DirtyChannel` machinery — coalescing, selective fan-out, re-entrancy handling, error isolation — is written once in the engine and reused by both.

`@blac/core` is a consumer of `@dirtytalk/structural`: BlaC's per-consumer path tracking is that package's path-set model. BlaC also re-exports [`untracked`](/react/dependency-tracking) from it.

All three are standalone and framework-agnostic — usable with no React and no BlaC — but they are documented here only at this level. For BlaC itself, start at [the introduction](/guide/introduction).