Add CSS if font does not load

With document.fonts.ready.then, it is possible to change CSS if a font is loaded.

Example:

document.fonts.ready.then(function() {
  $("div").css("color", "blue");
});
@font-face {
  src: url("https://s3-us-west-2.amazonaws.com/s.cdpn.io/133207/moderna_-webfont.ttf") format("truetype");
  font-family: "font";
}

div {
  font-family: "font";
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>

<div>Lorem ipusm</div>

Now my question is:
Does something like document.fonts.NOT.ready.then exist? Or how can I change the CSS if the font gets not loaded?

Would be very thankful for help.