1. A concise explanation of the problem you're experiencing.
i want to know there is any liberary of cesiumjs through which i can create a polyline , polygon and create a GEOJSON data?
2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.
3. Context. Why do you need to do this? We might know a better way to accomplish your goal.
4. The Cesium version you're using, your operating system and browser.