how to write a es6 class extend Cesium.viewer

1. A concise explanation of the problem you’re experiencing.

I am developing a project using es6

I want to write a class extend Cesium.viewer

my code snippet is below

2. A minimal code example. If you’ve found a bug, this helps us reproduce and repair it.

import Viewer from "cesium/Source/Widgets/Viewer/Viewer"
class EasyViewer extends Viewer {
    constructor(container, options) {
        super(container, options);
    }
}
export default EasyViewer;

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.

I create a project using vue

4. The Cesium version you’re using, your operating system and browser.

cesium version is 1.16.0

You may need to use a wrapper to get this work. While there isn’t an official one, there are some community ones like: https://www.npmjs.com/package/vue-cesium

You may also find this article helpful on what it takes to get CesiumJS working in webpack: https://cesium.com/docs/tutorials/cesium-and-webpack/#add-cesiumjs-to-a-webpack-app