Bar Chart
This bar chart visualizes population data from a CSV file, mapping each country’s population value to a rectangle. The code uses D3 v7’s `csv` loader, `scaleLinear`, and `max` functions to process the data, converting population values to numbers and multiplying by 1,000. It renders fixed-size 300x300 SVG rectangles, which do not yet encode the data proportionally—a partial implementation of the chart. The React-free example relies on selecting an SVG element and appending rects via `selectAll` and `enter`.