Kotes@kotaro@kotaro.me
I learned on MDN that event listeners themselves are asynchronous, so I didn't expect the callback to be synchronous.
However, that's something I would have realized if I had just stopped to think about it for a moment.
The reason I can usually treat an event listener's callback as if it were synchronous without giving it a second thought is that by default, it's a synchronous function.
I was under the misconception that anything with an arrow syntax like => was an asynchronous process.