> env.QUEUES[1 + hour % 2]

// results in index 1 or 2 as js has precedence for */% over +-

So something like the following, for your desired visual succinctness? ...

env.QUEUES[hour % 2 ^ 1]

// results in desired js index 0 or 1

I wonder if any of you using AI code assistance regularly might tell an old hack like me if your code review tools would have caught such a bug?