This map_comparison repo includes R code for generating two interactive maps with address search and "before and after" sliders. R script with the code is generate_maps. Demonstration data in the data directory is from the city of Framingham, Massachusetts, looking at current and redistricted precincts and maps - current from 2018 boundaries and "adopted" based on a Framingham City Council vote in December 2020 following the 2020 decennial US Census results.
You can see the resulting interactive map in the maps.html file (or in the GIF below). Click the magnifying-glass search icon at the top left to search for a specific address (you need to start typing the partial address and wait for drop-down selections to appear, and then choose the correct selection. This is not like the Google Maps Web page where you can enter any free-form address and have it work.) Click and drag the slider side by side to go between current (left side) and new (right side). The map would need to be placed on a page with titles explaining all this, which can be easily done using R Markdown.
