[Bug]: Next button throws a runtime error instead of cycling to the first sculpture

Summary

On the State: A Component's Memory page, the Sculpture Gallery example allows users to navigate through sculptures using the Next button. The gallery works correctly while navigating through valid entries, but when the user clicks Next on the final sculpture (12 of 12), the application does not cycle back to the first sculpture.

Instead, the index exceeds the sculpture list bounds, making sculpture undefined and causing the runtime error:

App.js: can't access property "name", sculpture is undefined

Expected: The gallery should wrap around from the last sculpture to the first sculpture when Next is clicked.

Actual: The application throws a runtime error because it attempts to access properties such as sculpture.name on an undefined object.

Affected screen: React.dev → Learn React → Adding Interactivity → State: A Component's Memory → Sculpture Gallery example.

Page

https://react.dev/learn/state-a-components-memory

Details

No response

State: A Component's Memory ページを開いて Sculpture Gallery の例を確認し、sculpture 12 of 12 で Next をクリックしてエラーを再現します。例のインデックス更新を追跡し、ギャラリーが未定義のエントリにアクセスせずに最初の彫刻に戻ることを確認します。