Bromin,
<script>
var channels = ['channel1', 'channel2', 'channel3', 'channel4'];
var commands = ["hello", "goodbye", "send", "countdown", "backcountdown"];
var ready = true;
var f = a => [a, ready];
var com = channels.map(f);
var cooldown = Object.fromEntries(com);
cooldown = Object.fromEntries(commands.map(c => [c ,{ready, cooldown}]));
document.write(JSON.stringify(cooldown, "", 4));
</script>