C# extension translation to JS?

Hello Everyone,

So I've been following a rather good tutorial from Pixelnest studios about the new 2D framework in Unity. I've gotten to the part where I'm implementing parallax scrolling. The tutorial is written in C# but I'm only familiar with Javascript so I've been able to rewrite their tutorial as we go. Except at this point. The tutorial talks about programming a C# Renderer Extension script. Here's the script:

 using UnityEngine;
 
 public static class RendererExtensions
 {
   public static bool IsVisibleFrom(this Renderer renderer, Camera camera)
   {
     Plane[] planes = GeometryUtility.CalculateFrustumPlanes(camera);
     return GeometryUtility.TestPlanesAABB(planes, renderer.bounds);
   }
 }

My question is simply, is this script something that can be translated into JS? Or because it's a C# extension, does it have to remain in C# or what?

Thanks ahead of time for your help! -Kaze-