What is React Reconciliation? How does it work? What criteria does React use to decide whether to update or remount a component?

React Reconciliation is the process of comparing the new virtual DOM with the previous version to determine the minimal changes needed to update the real DOM.

How it works:

• When state or props are updated, React creates a new virtual DOM.
• Then React compares the new virtual DOM with the previous one (diffing).
• Based on the differences, React decides which parts of the real DOM need to be updated and which can remain unchanged.

Criteria for updating or remounting a component:

• If the component type (e.g., div, span, or custom component) changes, React will remove the old one and create a new element.
• If the type remains the same, React will only update the changed props and state.
• For class components, React calls lifecycle methods to determine if an update is necessary.
• For functional components with hooks, React compares state and props.

Thus, React minimizes DOM operations, enhancing performance.