Create a basic graphic js drawing app exporting valid GrandOrgue console files.

I need to write a software that allows to draw and export console definitions for the GrandOrgue software. This software is a Pipe Organ emulator. But this project wil lonly create graphic layouts for it. We need to write like a drawing app, in which you can define a background, and put buttons, knobs, sliders which have some properties. So we should be emulating what the program draws in the main screen. Tehe is a library of CC licensed components to choose from. When the user is satisfied with the layout, we should be able to save the internal drawing state, and export this layout to a valid Grandorgue file (without sounds, the software should open the graphic console only) The output format is in the application's help, I can provide guidance on how to employ it, etc. Many thanks.