How to get the terrain height at mouse position when in 2D map? - cesiumjs

Question

I'm using Cesium in 2D mode.
This is the code I'm using to take the terrain height at mouse position:
cartographic = Cesium.Ellipsoid.WGS84.cartesianToCartographic( position );
var longitudeString = Cesium.Math.toDegrees(cartographic.longitude).toFixed(10);
var latitudeString = Cesium.Math.toDegrees(cartographic.latitude).toFixed(10);
mapPointerLatitude = latitudeString.slice(-15);
mapPointerLongitude = longitudeString.slice(-15);
var tempHeight = cartographic.height;
if( tempHeight < 0 ) tempHeight = 0;
mapPointerHeight = tempHeight.toFixed(2);
Where position came from a Cesium.ScreenSpaceEventType.MOUSE_MOVE event:
if ( mapStyle === '2D' ) {
var position = viewer.camera.pickEllipsoid(movement.endPosition, scene.globe.ellipsoid);
if (position) {
return position;
}
}
if ( mapStyle === '3D' ) {
var ray = viewer.camera.getPickRay(movement.endPosition);
var position = viewer.scene.globe.pick(ray, viewer.scene);
if (Cesium.defined(position)) {
return position;
}
}
When the map is in 3D mode (Cesium.SceneMode.SCENE3D) I have the height value in tempHeight but when the map is in Cesium.SceneMode.SCENE2D this value is always zero. What I'm doing wrong?
EDIT
Don't know if this is the best way but I get it to work putting my code inside this:
cartographic = Cesium.Ellipsoid.WGS84.cartesianToCartographic( position );
var positions = [ cartographic ];
var promise = Cesium.sampleTerrain(terrainProvider, 11, positions);
Cesium.when(promise, function( updatedPositions ) {
// PUT ALL HERE
});

Answer 1

You can actually try Cesium.sampleTerrainMostDetailed to get more precise altitude.
// Query the terrain height of two Cartographic positions
const terrainProvider = Cesium.createWorldTerrain();
const positions = [
Cesium.Cartographic.fromDegrees(86.925145, 27.988257),
Cesium.Cartographic.fromDegrees(87.0, 28.0)
];
Cesium.sampleTerrainMostDetailed(terrainProvider, positions).then((updatedPositions) => {
// positions[0].height and positions[1].height have been updated.
// updatedPositions is just a reference to positions.
})
https://cesium.com/learn/cesiumjs/ref-doc/global.html?classFilter=sample#sampleTerrainMostDetailed