小编Zig*_*ate的帖子

.findOne()我将 Mongoose 更新到最新版本（6.0.1），现在每当执行时都会收到此错误：

MongooseError: Query was already executed: Streams.findOne({ i: 6 })
    at model.Query._wrappedThunk [as _findOne] (C:\Users\honza\ZiggerTestMaster\node_modules\mongoose\lib\helpers\query\wrapThunk.js:21:19)
    at C:\Users\honza\ZiggerTestMaster\node_modules\kareem\index.js:370:33
    at processTicksAndRejections (node:internal/process/task_queues:78:11)
    at runNextTicks (node:internal/process/task_queues:65:3)
    at listOnTimeout (node:internal/timers:526:9)
    at processTimers (node:internal/timers:500:7) {
  originalStack: 'Error\n' +
    '    at model.Query._wrappedThunk [as _findOne] (C:\\Users\\honza\\ZiggerTestMaster\\node_modules\\mongoose\\lib\\helpers\\query\\wrapThunk.js:25:28)\n' +
    '    at C:\\Users\\honza\\ZiggerTestMaster\\node_modules\\kareem\\index.js:370:33\n' +
    '    at processTicksAndRejections (node:internal/process/task_queues:78:11)\n' +
    '    at runNextTicks (node:internal/process/task_queues:65:3)\n' +
    '    at listOnTimeout (node:internal/timers:526:9)\n' +
    '    at processTimers (node:internal/timers:500:7)'
}

我的代码如下：

var visitorData = Visitor.find({});
    
app.get("/retrieve", function(req,res){
    visitorData.exec(function (err,data) {
        if (err) { …