[bmeck]

There is a pretty epic thread that I suggest you just read the tail end of https://github.com/nodejs/node-eps/pull/3#issuecomment-21476... . Basically we tried detection via source code as the first proposal; ambiguities at runtime that do not throw errors make it absolutely impossible to do safely, performance problems, and tooling integration problems.

[gedy]

Subjective, but .mjs just sounds horrid..

[bmeck]

We looked at several alternative extensions and it was the least egregious of them: https://github.com/nodejs/node-eps/blob/master/002-es6-modul...