This example demonstrates how to load external data in a React application using D3, displaying the loaded dataset’s size, row count, and column count in a large <pre> element. The app uses React’s useState and useEffect hooks to manage the data state and trigger the asynchronous fetch, while d3.tsv loads the CSV file from a GitHub gist URL. A separate message.js module formats the summary using d3.tsvFormat, and the interface initially shows “loading” until the data arrives.