Coronavirus Deaths by Country over Time (with Voronoi Hover)
This example displays cumulative COVID-19 deaths per country over time using a log-scaled line chart. A Voronoi overlay, constructed with `d3.Delaunay`, enables precise hover detection across all data points, highlighting the nearest country’s line and displaying a tooltip with the death count, country name, and date. The chart uses `d3.scaleTime`, `d3.scaleLog`, and `d3.line` with React for rendering, pulling timeseries data from the Johns Hopkins COVID-19 dataset.