} else {
// if already flushing, splice the watcher based on its id
// if already past its id, it will be run next immediately.
let i = queue.length - 1
while (i >= 0 && queue[i].id > watcher.id) {
i--
}
queue.splice(Math.max(i, index) + 1, 0, watcher)
}
// queue the flush
if (!waiting) {
waiting = true
nextTick(flushSchedulerQueue)
}
}
}
