Passing information: create a child component that updates its parent's state, which then updates a sibling component.

Passing information: create a child component that updates its parent's state, which then updates a sibling component.

• A. It cannot be done.
• B. Siblings cannot be updated from the parent's state.
• C. Directly mutating the DOM of the sibling updates it.
• D. Elevate the shared state to the parent and pass it down as props to both children.

Answer: (D)

Lifting state up to a common parent is the pattern that makes two sibling components stay in sync. The child updates the shared data by calling a function provided by the parent; the parent stores that data in its state and passes the current value down to both children as props. When the state changes, React re-renders the children with the new props, so the second child reflects the update immediately. Directly mutating the DOM of a sibling isn’t how React handles updates and won’t reliably trigger a re-render. By elevating the shared state to the parent and passing it down, both children stay in sync through a single source of truth.

Lifting state up to a common parent is the pattern that makes two sibling components stay in sync. The child updates the shared data by calling a function provided by the parent; the parent stores that data in its state and passes the current value down to both children as props. When the state changes, React re-renders the children with the new props, so the second child reflects the update immediately. Directly mutating the DOM of a sibling isn’t how React handles updates and won’t reliably trigger a re-render. By elevating the shared state to the parent and passing it down, both children stay in sync through a single source of truth.