This bar chart shows the top 20 lead sponsors of affordable housing in San Francisco. The brushing and scrolling feature allows to focus on the data you're more intrested in and investigate it further. Hovering over the bar shows the little tooltip with the company name and the number of affordable units they're responsible for. The bar chart shows that the biggest contributors to the affordable housing program are Related California, a for-profit construction company that speicalizes in luxury appartments beats Tenderloin Neighborhood Development Corporation , an organization dedicated to providing affordable housing that's been in San Francisco since 1981.
In order to get the sum of the provided affordable apartments by sponsor, I had to nest the data by sponsor and calculate the sum of all the units they're providing. After getting the data from the nest function, I logged it to a console and copied it over to the source code as an array of objects, since it made it a lot easier to update the bars on brushing and filtering.