Convert Image data to PolyData

Hello, I have this volume which I added labels on it in the regions I want, I want to extract only the painted regions and convert them to polydata in order to make them surface and then computing their volume, I found a filter in C++ that converts vtkImageData to vtkPolyData, but I can’t find the way inside VTK.js, any help?

image

You could look at vtkImageMarchingCubes. If that’s not the filter you found in VTK C++, then which one is it that doesn’t exist in vtk.js?