> I might accomplish this by dropping support for the Internet Explorer family of browsers.

I was just working on some legacy stuff last week. Only worked in IE11, in compatibility mode. I had to use vanilla JS to get some data out of a huge form.

Yeah, document.querySelector('#app') doesn't work. I found out, "It only works on modern browsers" which IE11 doesn't qualify as, which is kind of funny to me. I ended up using document.getElementById('app') instead though, which did work.