Mongoose 错误： Right-hand 'instanceof' not callable 错误

Question

我在mongoose中设定用户的comment结构为：

[
    [{1}, {2}, ...],
    [{4}, {5}, ...],
    ...
]

假设我回复5这条评论，便找到该用户的comment(即上段结构)，map第一遍，map第二遍找id是否对应：

        let result = User.findOne({name:blog}).then((item) => {
                        let reply_to = reply_to_id ? reply_to_id[0] : ''
                        console.log('reply_to', reply_to)

                        // item.comment 结构：[ [{_id1},{_id2},{...}], [{},{},{}], ... ]
                        // 如果是回复评论 则查询
                        if (reply_to)
                            if (item.comment.length > 0)
                                // 遍历外层数组
                                item.comment.map((comments, comments_index) => {

                                    // 遍历内层数组
                                    if (comments.length > 0)
                                    comments.map((comment, comment_index) => {

                                        // 找到被回复的 comment
                                        if (comment._id == reply_to) {
                                            // 能输出相应结果，但下句报错
                                            console.log(comment._id == reply_to, comments_index, comment)

                                            // 报错：Unhandled rejection TypeError: Right-hand side of 'instanceof' is not callable
                                            item.comment[comments_index].splice(
                                                    item.comment[comments_index].length-1, 
                                                    0, 
                                                    {
                                                        name:         username,
                                                        date:         new Date(),
                                                        message:     message,
                                                        picture_url:     [],
                                                        like_number:     0,
                                                        diskile_number: 0,
                                                    }
                                            )
                                            console.log(item.comment[comments_index])
                                        }
                                    })
                                })
                                ......

报错如下，找遍了git、Cnode毫无头绪：

Unhandled rejection TypeError: Right-hand side of 'instanceof' is not callable
    at Array._cast (C:\nodejs\myblog\node_modules\mongoose\lib\types\documentarray.js:103:15)
    at Array.splice (C:\nodejs\myblog\node_modules\mongoose\lib\types\array.js:565:20)
    at comments.map (C:\nodejs\myblog\models\UserActions.js:160:41)
    at Array.map (native)
    at item.comment.map (C:\nodejs\myblog\models\UserActions.js:156:19)
    at Array.map (native)
    at User.findOne.then (C:\nodejs\myblog\models\UserActions.js:153:22)
    at tryCatcher (C:\nodejs\myblog\node_modules\bluebird\js\release\util.js:16:23)
    at Promise._settlePromiseFromHandler (C:\nodejs\myblog\node_modules\bluebird\js\release\promise.js:512:31)
    at Promise._settlePromise (C:\nodejs\myblog\node_modules\bluebird\js\release\promise.js:569:18)
    at Promise._settlePromise0 (C:\nodejs\myblog\node_modules\bluebird\js\release\promise.js:614:10)
    at Promise._settlePromises (C:\nodejs\myblog\node_modules\bluebird\js\release\promise.js:693:18)
    at Async._drainQueue (C:\nodejs\myblog\node_modules\bluebird\js\release\async.js:133:16)
    at Async._drainQueues (C:\nodejs\myblog\node_modules\bluebird\js\release\async.js:143:10)
    at Immediate.Async.drainQueues (C:\nodejs\myblog\node_modules\bluebird\js\release\async.js:17:14)
    at runCallback (timers.js:672:20)
    at tryOnImmediate (timers.js:645:5)
    at processImmediate [as _immediateCallback] (timers.js:617:5)

各位仁兄能否指点一下，小弟感激不尽，卡了一天了毫无进展

Answer 1

使用 es6 的 promise 替换掉 mongoose 自带的promise：mongoose.Promise = global.Promise;
并且在mongoose所有返回为query的方法使用promise时，加上 .exec()，比如：User.findOne({name:blog}).then() 改为 User.findOne({name:blog}).exec().then()试试。

Answer 2

item.comment[comments_index] 这个debug 输出是什么？
这个地方按理说 不应该涉及到promise,mongoose啊，我感觉按照语义是 右边不是一个不可返回。。。