alt Hacker News> I'm of opinion if you start writing OS userland in either javascript or python (or both), you should be fired on the spot, but I don't make the shots.
KDE Plasma, which is in my opinion the most advanced desktop environment is written in Qt QML which is JavaScript. There are advantages to that over C++, namely your session won't simply crash.
QML is not JavaScript.
(While you can use some JavaScript from QML, the application still have a C++ core. QML applications can still crash. There is no DOM with QML, no browser overhead)