React does not "iterate over parts" of your functions, it simply calls the entire function. There is no magic happening.
You've already received a lot of responses explaining how both const works (which you still seem to misunderstand) and how React works, I hope you can take this as an opportunity to learn and perhaps not be so confident in the future when criticizing something that you clearly haven't taken time to even understand at a basic level.
You've already received a lot of responses explaining how both const works (which you still seem to misunderstand) and how React works, I hope you can take this as an opportunity to learn and perhaps not be so confident in the future when criticizing something that you clearly haven't taken time to even understand at a basic level.