在Mongoose中填充后实现查询时出错

Question

您好，最近我问了一个问题： How can i find documents by populated field? 什么是重复的结果： Querying after populate in Mongoose

我已经有

PolicySchema.statics.lookup = async function({path, query})  {

  const rel =
    mongoose.model(this.schema.path(path).options.ref);

  const pipeline = [
    { '$lookup': {
      'from': rel.collection.name,
      'as': path,
      'let': { [path]: `$${path}` },
      'pipeline': [
        { '$match': {
          ...query,
          '$expr': { '$in': [ '$_id', `$$${path}` ] },
        }},
      ],
    }},
  ];
  console.log(JSON.stringify(pipeline));
  console.log(await this.aggregate(pipeline).exec());
};

我从日志管道中获得

[
   {
      "$lookup":{
         "from":"companies",
         "as":"company",
         "let":{
            "company":"$company"
         },
         "pipeline":[
            {
               "$match":{
                  "company.name":{
                     "$eq":"Test"
                  },
                  "$expr":{
                     "$in":[
                        "$_id",
                        "$$company"
                     ]
                  }
               }
            }
         ]
      }
   }
]

但是它为我返回了所有策略（“公司”字段为空），但只有其中一个拥有名为Test的公司：(
便于理解的屏幕截图：https://paste.pics/73efbe10afefc1963dcf75e312e95663