Find the $x$- and $y$-intercepts of the graph of the equation $y=x + 4$.

The $x$-intercept(s) have $x =$
Note: If there is more than one, give a comma separated list. If there are none, type none .

The $y$-intercept(s) have $y=$
Note: If there is more than one, give a comma separated list. If there are none, type none .