This is a case of developper ignorance, not missing tools: v8 has an integrated debugger since 2009, and you can interact with it using the Chrome developer too

This is a case of developper ignorance, not missing tools: v8 has an integrated debugger since 2009, and you can interact with it using the Chrome developer tools, probably the most used debugger frontend of all. There are also debuggers for PHP :) No horse in this race, I write Python.