The package.json in that repository says "MIT". How does that work with the propietary license agreement?
I also wonder if the author has any way to prevent copyleft code entering their project. What would be a nuisance for a free software project could potentially kill a commercial one like this.
I do not mean this as a comment against copyleft or this particular project, I am really interested to know if there is a Semi-Automatic license scanner.