real-world-code.js

export default function Note() { // creating a function
    const match = useRouteMatch(); // calling a function and saving it in a variable
    const { noteId } = useParams();
    const note = useSelector(state => state.notes.find(n => n.id === noteId)); // calling a function with a parameter
    
    return ( // returning something from a function
        <div className="container mt-3">
            { (!note) ? <Redirect to="/notfound"/> :
                <Switch>
                    <Route path={`${match.path}/edit`}>
                        <NoteForm key={note.id} note={note} />
                    </Route>
                    <Route path={`${match.path}`}>
                        <NoteView key={note.id} note={note} />
                    </Route>
                </Switch>
            }
        </div>
    )
}