Extending Cesium classes

CesiumJS
1

Just wondering if there is another way I haven't come across yet to easily extend the base Cesium classes to add new functionality. For instance, if I wanted to make a custom class called MyEntity that extends the base Entity class, can I do that?

I've tested doing this. I accept the object that would be used to create the entity as a parameter in my class and then pass it to the super() call to create the Cesium Entity. All that seems to work but when I attempt to add my new MyEntity object to the viewer I get an error that name is a reserved keyword.

I've gotten this to work with another class or two but Entity seems to be giving me trouble. Is there something stupid I'm missing?

2

Can you post some of your code?

I just tried this out with the examples described here https://kevhuang.com/subclasses-and-inheritance-in-javascript/ and this creates a “MyEntity” that will add a default red material to a rectangle:

var MyEntity = function(options) {
if (options && options.rectangle) {
options.rectangle.material = Cesium.Color.RED.withAlpha(0.5);
}

Cesium.Entity.call(this, options);

};
MyEntity.prototype = Object.create(Cesium.Entity.prototype);
MyEntity.prototype.constructor = MyEntity;

``

Here’s a full example on Sandcastle. Let me know if that helps!

3

I mean yeah, that can work. I was hoping to use the cleaner, class implementation where I could do..

class MyEntity extends Cesium.Entity {
   constructor() {
      super()
   }
}

And define things from there but I guess I could go ahead and just extend it using the prototype.

Thanks

4

That would definitely be nice, and in fact is on our roadmap, see https://github.com/AnalyticalGraphicsInc/cesium/issues/2524#issuecomment-363495391