I think the difference is that when a C programmer hits an undefined behaviour, they either blames the spec, the compiler, or themselves. A JavaScript programme

I think the difference is that when a C programmer hits an undefined behaviour, they either blames the spec, the compiler, or themselves. A JavaScript programmer doesn't need a prompt to blame the spec proliferation and dilution, the necessity to write cross-platform by default, and their lack of foresight in not including a 3rd-party library that would have provided some vestiges of a targetable platform. The C code that started as a nice asprintf(3) for GNU/Linux will sprout a few if-defs once it has to run on some embedded PoS without a sane malloc().