My fix doesn't actually fix the "/* */" issue, unfortunately. However, it doesn't break "//" either; note that comment-multi-line is t for e.g. c-mode, and comment-indent-new-line works for "//" there.
> js-mode doesn't set the comment-multi-line variable. This results inIf I understand and remember correctly, this is not the right fix for
> comment-indent-new-line behaving improperly when used in a multi-line
> comment, which also affects auto-fill-mode, according to the documentation
> for comment-multi-line.
your problem: setting comment-multi-line to t will fix your problem with
"/*..*/" but will introduce another for "//....\n" and vice-versa.
Stefan