如何在猫鼬填充查询中获得计数

Question

我想知道如何在填充查询中获得计数，在这里仅获得填充数据计数，代码示例如下并输出

我使用猫鼬填充方法

exports.getPost = async (req, res) => {
  try {
    const user = await User.findOne({_id:req.params.user_id, status:1})
    if(typeof user !== 'undefined' && user !== null){
      const userPost = await User.find({_id:user._id, status:1},{_id:1,image:1,name:1})
      .populate('positions',{_id:0,profile_name:1},{status:1})
      .populate('posts',null,{status:1},{sort:{'createdAt':-1}}).exec(function(err, postData){
        if(err){ console.log(err); }
        async.forEach(postData, function(users, callback){
          Post.populate(users.posts, {path: "comments", match:{status:1},select:{_id:1}}, function(err, comments){
            if(err){ console.log(err); }
            Post.populate(users.posts, {path: "likes", match:{like:true},select:{_id:1}}, function(err, likes){
              if(err){ console.log(err); }
              callback();
            });
          });
        }, function(err){
          res.status(200).json({
            error: false,
            message: "Post get successfully.",
            users: postData
          });
        });
      });
    }else{
      res.status(500).json({
        error: true,
        message: "Wrong user id"
      });
    }
  } catch (e) {
    helper.errorLogs("Get Post", "GET", req.protocol+'://'+req.get('host')+''+req.url, req.params.user_id, e.message, e.stack);
    res.status(400).json({
      error: true,
      message: e.message
    });
  }
}

当前结果是：

{
    "error": false,
    "message": "Post get successfully.",
    "users": [
        {
            "image": null,
            "positions": [],
            "posts": [
                {
                    "comments": [
                        {
                            "_id": "5d71e288d2577012adb0675c"
                        },
                        {
                            "_id": "5d71e539e0c625171dde4a34"
                        }
                    ],
                    "likes": [
                        {
                            "_id": "5d71f301697636220d73d339"
                        }
                    ],
                    "status": 1,
                    "_id": "5d70f263c977a3579bd296a5",
                    "user_id": "5d70ecfd699c1056424218ff",
                    "post": "A morning could change that story entirely, though.",
                    "image": "https://honeycombapi.iapplabz.co.in/5mmid32qdff_1567766507302.jpeg",
                    "createdAt": "2019-09-05T11:32:51.981Z",
                    "updatedAt": "2019-09-06T10:41:47.307Z",
                    "__v": 4
                }
            ],
            "_id": "5d70ecfd699c1056424218ff",
            "name": "anil"
        }
    ]
}

，预期结果如下：

{
    "error": false,
    "message": "Post get successfully.",
    "users": [
        {
            "image": null,
            "positions": [  ],
            "posts": [
                {
                    "comments": "2",
                    "likes": "1",
                    "status": 1,
                    "_id": "5d70f263c977a3579bd296a5",
                    "user_id": "5d70ecfd699c1056424218ff",
                    "post": "A morning could change that story entirely, though.",
                    "image": "https://honeycombapi.iapplabz.co.in/5mmid32qdff_1567766507302.jpeg",
                    "createdAt": "2019-09-05T11:32:51.981Z",
                    "updatedAt": "2019-09-06T10:41:47.307Z",
                    "__v": 4
                }
            ],
            "_id": "5d70ecfd699c1056424218ff",
            "name": "anil"
        }
    ]
}