Three.js camera zoom

I am new in Canvas and Three.js. I am working with OrbitControls and Camera zoom and am wondering how to get the camera zoom once the mouse wheel change it.
Here the sandbox.
I expected the camera.zoom property changes once the wheel is rotated, but it always remains 1.
ChatGPT tells me I have to set it. Really?

I don’t think you’re zooming with the controls if you are using a perspective camera. You are doing a “dolly”. You may want to change your field of view if you want to zoom. An orthographic camera on the other hand should change the zoom when used with the controls.

I understand what you mean, but since I am new, I dont really know how to do it. Could you give me some details or show me an example?