What "shape" is your project? It's not overall complexity that matters. It’s the ratio of complexity of functionality to visibility into that functionality.
My PC wouldn’t boot, didn’t even make a sound. I eventually traced the problem down to a particular mounting screw. But how did I figure it out? Debugging!
There's been a lot of effort to add ES6 compatibility to browsers (and Node.js). I'm going to use three Node debugging techniques modified to work with ES6.
Let’s assume we have a daemon running on some kind of POSIX system written in Ruby that works great most of the time, but every few months gets “stuck."