Initially I used chart.js to paint the charts but I had to introduce it so many flags (no label Transformation, sensitive spacing etc) that I reverted to do it myself (even though I also have a working version with an altered chart.js).

I am using node-drawville which provides an Html5 canvas Api abstraction over the terminal. D3 uses svg so it is not adequate. However I did saw a port of d3 to canvas which I didn't had time to check.