I hadn't heard of it before, and it does look potentially very powerful.

My only initial concern from reading the quick start (http://www.sikulix.com/quickstart.html) is the apparent requirements to use the "SikuliX IDE" for scripting...

The magic of Sikuli is its use of the OpenCV library under the hood (and Tesseract for OCR). You could skip the Sikuli part and just use OpenCV and Tesseract directly. (Not easy, but theoretically possible.)

I once used sikuli to extract a table from a pdf. Pretty funny way of hacking a fast solution for a problem. It's a pretty powerful tool but not very stable. IDE is also not so exciting but gets the job done. Pretty excited to see how far this project will go.

You actually don't need to use their IDE as the scripts it generates are just python scripts.

I've used it a few times in the past and was able to use an external screenshot program (Apple-Shift-4 on Mac) and a text editor to write the scripts.

Check out Morgan Dixon's awesome research project Prefab: The Pixel-Based Reverse Engineering Toolkit, which would be great to integrate into RobotJS.

http://homes.cs.washington.edu/~mdixon/research/prefab/

Sikuli is awesome, I've used it a bunch. But developing and distributing cross platform commercial applications with it is a mess. Also interacting with other languages, to make a GUI for example, isn't fun.