State lifecycle React Questions

Understand the difference between props and state in React, when to use each, and how they interact to drive rendering.

Correctly add items to an array in React state using spread, concat, or functional updates without mutating the original array.

Use useEffect with an empty dependency array to run logic once after the first render, equivalent to componentDidMount.

Understand what hooks are, the rules that govern them, and how useState and useEffect replace class component state and lifecycle methods.

Understand what triggers React re-renders, how to use state and props correctly, and how to prevent unnecessary re-renders.

Use useEffect to run logic after state updates, and useLayoutEffect when you need to act before the browser paints.

Use useEffect without a dependency array to run logic after every render, and understand when this pattern is appropriate versus problematic.

Use useReducer, a counter state, or the key prop to force a component to re-render or fully reset without relying on useState directly.