A digital garden by Sina Salahshour
Notes, deep dives and explainers, published straight from my Obsidian vault. Diagrams, footnotes and the occasional rabbit hole.
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A source-level tour of how React 19 turns your components into pixels, from createRoot and lanes to fibers, hooks, the commit phase and the React Compiler.
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React does its work in two phases. The render phase is pure and can be interrupted (in practice only for transition, retry and idle work, because the first mount and clicks render…
A click reaches React through the listener createRoot put on the container. dispatchDiscreteEvent sets the update priority to Discrete, so setCount gets SyncLane. The update is…
createRoot(el).render(<App/>) renders nothing synchronously. It builds the root objects, attaches the event listeners, queues one DefaultLane update and books a microtask. The…
A function component's first render runs inside renderWithHooks. It points the global hooks dispatcher (ReactSharedInternals.H) at the mount implementations, then calls your…
react is a small package. It builds plain element objects (jsx()) and holds one shared mutable object, ReactSharedInternals, with slots like H (the hooks dispatcher) and T (the…
A fiber is a mutable, long-lived object for one instance of a component, host element or text node. It is one unit of work and also one node in a tree. Fibers are linked with child…
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