Nice! Are you using any specific canvas libraries for this, like KonvaJS? I recently worked on a closed-source project that used Konva and was pretty impressed with its capabilities. HTML canvas is powerful stuff if you know what you're doing.

Right now it supports rack layouts, fibre and power cables, and topology building with drag-and-drop editing. I will probably end up adding splice management/ODF/closures too but curious what others would find useful.