Inconsistent behavior with module.exports and callback function in documentation example

[SebastianAviles]

I tried running a file as described in the documentation. Originally, my file looked like this:

module.exports = (callback, message) => {
    ...
    callback(null, message);
};

But when I ran it, it threw the error "module.exports is empty." I had to change my code like this:

function myfunction(callback, message) {
    ...
    callback(null, message);
}
exports { myfunction }

This worked, but now it throws an error saying that callback is not a function. So, I had to make the following change:

function myfunction(callback, message) {
    ...
    return message;
}
exports { myfunction }

This works, but it's completely different from the approach shown in the documentation.