detectar cambio de orientación con javascript

orientacion.js

window.addEventListener("orientationchange", function() {
    console.log("the orientation of the device is now " + screen.orientation.angle);
});

window.addEventListener("orientationchange", function() {
if (window.orientation == 90 || window.orientation == -90) {
    console.log('landscape mode');
} else {
    console.log('portrait mode');
}
});