The need for that form of reasoning seems to me to be a symptom of the way that we go about writing code. We don't need to worry about if line 10 executes befor

The need for that form of reasoning seems to me to be a symptom of the way that we go about writing code. We don't need to worry about if line 10 executes before line 11 within a given scope -- we just know this. If we come up with a similarly simple way of writing asynchronous operations that have dependencies then we can read it just as fluently. In my experience, promises do fill this role if they're used in a suitable scenario.