Yea, modern JS... it's just a joke, no integers, still funny effects with []+[] and {}+{} and []+{} and {}+[]. Good luck with writing anything serious using such a crap.
But a whole bunch of 'serious' applications have obviously been written using JS, and it's a totally stupid view to think otherwise. Frankly the people who are the most concerned with 'my language is better than yours' litigation are by far the least productive developers I've encountered.
If you want to use constexpr in C++ you're going to have to upgrade your compiler as well, right (and, if you're unlucky, "migrate your project files" and all that mess)?
You couldn't be more wrong. The toolset that you need to develop decent C/C++ programs is massive and took decades to develop.