> I don't know enough coffeescript to be able to check this and it'd be > awesome if you could consider taking a look.
Coffeescript 2 creates ESM format js by default, adding -t option to coffee command should give you the old ES5 javascript like coffeescript 1.x
See https://salsa.debian.org/js-team/node-sockjs/-/blob/master/Makefile#L11
