This is not necessarily a React-related problem, though. Pretty much all operating systems do this. Even browsers do this internally to some degree as well as various spreadsheet applications and IDEs. Notepad has this… you can open a multi-gigabyte text file and the scrollbar is still pretty fast because you’re always reading a calculated segment of memory of the same size at a different location. In any software you naturally want to preserve memory to the visible set. But it doesn’t get crazy until you do this in video game software where you need to limit the visible set of triangles rendered on the screen from current camera angle with random geometry. Good write up :) Looking forward to more tutorials!