CodeVetter · Repo Unpack · Behavior traces
pmndrs/valtio
These traces follow source execution order across library and application boundaries. Counter startup and mutation demonstrate proxy construction and React notification, while both todo examples show action-to-render paths. The photo booth provides a concrete persistence lifecycle, and the documentation route demonstrates build-time compilation followed by rendering. DevTools and watch illustrate bidirectional external messages and reactive-effect cleanup.
- Counter startup: main.tsx imports App → module evaluation calls proxy({number:0}), assigns nested ticks, and starts a 200 ms interval → createRoot renders StrictMode/App → Figure and Ticks call useSnapshot and read separate properties.
- Counter increment: ButtonUp's onClick increments state.number → the set trap installs the value and notifyUpdate advances its version → subscribe schedules a microtask → useSnapshot compares affected reads and returns the snapshot used by Figure.
- Array todo addition: AddTodoInput.handleSubmit calls actions.addTodo and clears its input → addTodo pushes a generated numeric id into store.todos → useTodos reads useSnapshot(store) and applies the active filter → TodoList maps results into TodoRow.
- Map todo addition: form submission prevents default and rejects whitespace-only input → actions.addTodo calls store.todos.set with an id and completed:false → proxyMap.set writes a data slot and increments epoch → useTodos iterates snapshot values and TodoList renders TodoItem.
- Photo persistence: window load awaits loadImages then startMediaStream → capture draws video onto canvas and assigns a WebP data URL → acceptance calls saveImage and clears the candidate → the subscription snapshots images into localforage and redraws the gallery; later loadImages restores them.
- Documentation navigation: getStaticPaths calls getAllDocs/getSlugs with fallback:false → getStaticProps joins slug segments and calls getDocBySlug/getDocsNav → bundleMDX returns code/frontmatter → Doc renders DocLayout and MDXRenderer, which constructs the compiled component.
- DevTools lifecycle: devtools checks its enablement and extension → enables operations and connects → subscription sends snapshots for non-marker changes → ACTION JSON is assigned into live state, while jump messages set a time-travel flag → returned cleanup removes both subscriptions.
- watch lifecycle: watch creates cleanup/subscription sets and invokes revalidate → revalidate runs previous cleanups and calls callback(get) → get immediately subscribes newly used proxies → the parent context is restored before awaiting returned work → obsolete subscriptions are removed; cleanup stops further reevaluation.