JS/API code sample (covid-19)

View the source code in my Github repo

What is this? It’s easy to find daily tracking data for covid-19 infections, deaths, positive test rates, and so forth, but harder to tell how each state trending in comparison with each other. So while in lockdown, I put together these maps showing the percentage changes in Cases and Positive Test Rates versus 2 weeks ago for each state. (Both datasets are important, because sometimes an increase in cases was caused by an increase in testing, not increased spread of the virus.)

I originally compared total cumulative numbers, but changed the total case map to compare 7-day totals instead, which more accurately reflected recent case trends regardless of prior totals. If either of a state’s weekly counts is under 50, no data for the state is shown – trends in very low case counts are just statistical noise. Positive test rates still reflect total percentages, not weekly, because some states are unreliable in reporting that data as it comes in.

Hovering over a state (or clicking the state on a mobile device) gives you data for that state: past, current, and percentage change. The code should run on any site, if you update covid-maps-config.js with your Google Charts API key. In the same config file, you can also change the number of weeks to compare.

What technologies does it use?