This example demonstrates how React and D3 can work together to load and summarize data from an external API. The visualization shows the result of fetching a JSON dataset from an Azure-hosted solar financial analysis endpoint, then displaying the file size in kilobytes and the number of top-level keys in the data object. Using React’s `useState` and `useEffect` hooks, the app triggers a D3 `json()` request, stores the response in component state, and conditionally renders a loading message or the computed summary. The code uses ReactDOM for rendering and the `encodeURI` and `JSON.stringify` methods to calculate the data size.