The main thing you’re missing is the (real) functional programming style, which expects this kind of behavior when manipulating data. To refer to it as a refere

The main thing you’re missing is the (real) functional programming style, which expects this kind of behavior when manipulating data. To refer to it as a reference is somewhat misleading, functional programs are just dealing with a raw block of data, which is transformed into a new block of data. But to call it the old data and the new data is kind of silly, because it’s not really about state at all.