https://developer.mozilla.org/en-US/docs/Web/API/KeyboardEvent/keyCode states

You should avoid using this if possible; it's been deprecated for some time. Instead, you should use KeyboardEvent.code, if it's implemented. Unfortunately, some browsers still don't have it, so you'll have to be careful to make sure you use one which is supported on all target browsers.

event.keyCode shows up in places like

Unless there are any objections I will fork and work toward a PR to fix this.