¿Cuándo usa la ejecución de devolución de efectos
------------------------------------------------------------------------
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.
------------------------------------------------------------------------
KostasX