This example shows how to load and parse a CSV file using D3 within a React application, displaying the data in a simple SVG-based visualization. The code imports React hooks and D3 v5, using `d3.csv` to read data files containing GDP and population statistics from the World Development Indicators. Two separate heatmap instances are created, each with its own container and SVG element, demonstrating how the same visualization component can manage independent datasets. The approach relies on React's state management alongside D3's data-join and SVG manipulation methods to render the results.