Develop once, run everywhere was obviously not meant to be applied to backend code but to the client part. But besides that asynchronous IO is (usually) an OS-l

Develop once, run everywhere was obviously not meant to be applied to backend code but to the client part. But besides that asynchronous IO is (usually) an OS-level feature and there is really no need to surface these features with JavaScript, many other languages could and can do this as well.