“Когда используется return -return” Ответ

Когда используется return -return

------------------------------------------------------------------------
The useEffect returned function runs according to the dependencies array:
------------------------------------------------------------------------
- if it's empty [], on unmount.
- if it has dependencies [value1,value2], on dependencies 
  change (shallow comparison) and unmount.
- if it has no dependencies (no 2nd argument for useEffect) 
  it runs on every render and unmount.
------------------------------------------------------------------------