Let's understand when and how React components re-renders and solve a react interview quiz question around react component re-render cycle.
State Changes Always Cause Re-renders:
Not all state changes cause re-renders. React uses shallow comparison for state and props to determine if a re-render is necessary.
Props Changes Always Trigger Re-renders:
Similar to state, props changes trigger re-renders only if the new props are different from the previous ones based on a shallow comparison.
Parent Component Re-render Always Re-renders Child Components:
Child components only re-render if their props or state change, not necessarily when the parent re-renders.
Re-render Means DOM Update:
React's reconciliation process ensures that only the parts of the DOM that need to change are updated.
Understanding these misconceptions helps in optimizing React applications for better performance.