Virtualized Lists & Windowing Techniques

The same catalog, scrolled to the same row, held 210 rows with the default FlatList settings and 61 rows with one prop changed. That prop is windowSize, and the difference shows how much of a list's memory use you can control.

The previous chapter introduced the window, the range of rows that a FlatList keeps mounted around the screen. A list that works this way is called a virtualized list, and FlatList and SectionList are both built on a component named VirtualizedList. This lesson measures what each setting of the window does, so that you can tune it for a reason.