Vue.js 3 core framework (v3.5.43) — a TypeScript library for building user interfaces, organized as a pnpm monorepo. The codebase is split into focused packages: compiler-* (template → render function compilation), runtime-* (component model, virtual DOM patching, DOM platform bindings), reactivity (dependency-tracked state), server-renderer (SSR), and shared (internal utilities). The packages/vue directory aggregates the public API surface, while vue-compat provides Vue 2 compatibility mode.
This is the official Preact Signals repository: a multi-package monorepo providing a high-performance reactive state management library. The core package (`@preact/signals-core`) implements fine-grained dependency tracking using a linked-list-based reactive graph, with primitives like `signal()`, `computed()`, `effect()`, `batch()`, `untracked()`, `createModel()`, and `action()`. Framework-specific integrations exist for Preact (`@preact/signals`) and React (`@preact/signals-react`), including hooks (`useSignal`, `useComputed`, `useSignalEffect`, `useModel`), utility components (`Show`, `For`), and automatic Babel transforms that inject `useSignals` for seamless reactive re-rendering. In addition to the core and framework libraries, the repository includes a comprehensive developer tooling ecosystem: an ESLint plugin with six rules to prevent common signal anti-patterns, a debug package (`@preact/signals-debug`) that instruments signal internals for logging and DevTools integration, a Vite plugin (`@preact/signals-agent-vite`) that wires up debug clients and Babel transforms, and a full-featured DevTools UI (`@preact/signals-devtools-ui`) with a timeline, performance insights, and an interactive dependency graph. A browser extension embeds this UI into Chrome DevTools, communicating via adapters that support direct, postMessage, and extension messaging patterns. The codebase is well-structured with clear separation of concerns, extensive test coverage (unit, integration, and cross-framework), and active maintenance. While certain components are tightly coupled to the signals ecosystem, several patterns (adapter-based communication, graph layout algorithm, batch reconciliation logic) are isolated enough for extraction into other projects. The repository uses modern tooling (pnpm workspaces, Vitest, Babel, ESLint/Oxlint) and keeps up with framework versions, indicating low technical drift.