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
Lists and key
Rendering lists with map, choosing a key, an index as a key, resetting state with a key
Synthetic Events
Event handlers, SyntheticEvent, event delegation on the root and differences from DOM events
Working with Forms
Controlled and uncontrolled inputs, form Actions in React 19, form libraries
Composition Patterns
Composition, conditional rendering, compound components, render props and HOCs
Portals
createPortal, event bubbling through portals, modal accessibility
Error Boundaries
What error boundaries catch and what they don't, where to place them, how to reset them and react-error-boundary
Class Components and Lifecycle Methods
Legacy class components, lifecycle methods and their hook equivalents