We have a mid-size scale SPA and its suffering because of bloat. Functions are 2-500 lines long as an example. we've had critical bugs in the last 2 weeks and I got fed up and decided to start learning unit testing. Its been absolutely painful to get everything setup and started (Visual Studio). Nothing works. I would love to see a well written project to base my tests off of.
I would really love to see a well written SPA with testing, but I fear its almost reaching unicorn status. Most projects suffer from deadlines so they'll just never be written the way they should be and instead, the flow is now: patch it and move on.