Warning; very hacky.
Use any bonjour/zeroconf browser to find the host and ip of your sketch instance, then add it to test.js and run it. Sketch should then show a banner that this mirror is available. after that, every update to the current artboard will be rendered in the terminal using the image-to-ascii package, if you have problems installing the npm packages (i did) you should install GraphicsMagick first.