Waveforms in time line example in node.js

I came across this fine node.js example of working with audio waveforms in time line. I know most of the functionality has been covered in Shotcut already, however a few things maybe could be cherry-picked and included in Shotcut, like the Pro Tools types of fades/dissolves or faders/solo button in the track heads? Or maybe if the waveform drawing routine is faster in that example? What do I know… anyway here it is: