React in the Browser: react-dom
createRoot, hydrateRoot, hydration, StrictMode and flushSync
Components
Components, elements and JSX, purity, fragments
Props
Passing data and callbacks, default values, children, typing and prop drilling
State
useState and useReducer, state as a snapshot, batching, immutable updates
Working with Forms
Controlled and uncontrolled inputs, form Actions in React 19, form libraries
Portals
createPortal, event bubbling through portals, modal accessibility
Common Patterns
Composition, conditional rendering, compound components, render props, HOCs and error boundaries
Rendering and Reconciliation
Render and commit phases, virtual DOM, diffing heuristics and Fiber
Class Components and Lifecycle Methods
Legacy class components, lifecycle methods and their hook equivalents