我现在正在学习猫鼬，当我尝试从Player集合中填充Match集合中的players属性时，我遇到了一个问题，players属性返回一个空数组，我在各处寻找解决方案并且无法使它起作用。

这是“匹配模​​式”的一部分：

  ...
  corners_half2: {
  type: Number
},tackels_half: {
  type: Number
},tackels_half2: {
  type: Number
},cycle: {
  type: Number
},home_or_away: {
  type: String
},goals: [
  {
    minute: {
      type: Number
    },name: {
      type: String
    }
  }
],assist: [
  {
    minute: {
      type: Number
    },players: [
  {
    type: Schema.Types.ObjectId,ref: "Player"
  }
]
  },{
    timestamps: true
  }
);

和播放器模式：

const playerSchema = new Schema(
{
name: {
  type: String,required: true
},lastname: {
  type: String,required: true,minlength: 2
},total_time: {
  type: Number
},total_distance: {
  type: Number
},sprint_distance: {
  type: Number
},total_sprint: {
  type: Number
},sprint_avg: {
  type: Number
},goals: {
  type: Number
},assist: {
  type: Number
},cycle: {
  type: Number
}
  },{
    timestamps: true
  }
  );

const Player = mongoose.model("Player",playerSchema,"players");

填充功能：

app.get("/matches/:id",(req,res) => {
Match.findOne({})
.populate("players")
.exec(
  (err,doc) => {
    if (err) handleError(res,err.message,"Failed to get players");

    res.status(200).json(doc);
    console.log(req.params);
  }
);
});

播放器输出：

[
  {
    "_id": "5dc47f646463a124583006d1","name": "test2","lastname": "player","total_time": 16,"total_distance": 1.3,"sprint_distance": 0.3,"total_sprint": 7,"sprint_avg": 1,"goals": 3,"assist": 3,"cycle": 1,"createdAt": "2019-11-07T20:32:36.176Z","updatedAt": "2019-11-07T20:32:36.176Z","__v": 0
  }
]

匹配输出：

 {
  "players": [],"_id": "5dc5006d11fa703798b36f3b","team1": "fdsf","team2": "fsdfjdsd","goal_team1_half": 1,"goal_team2_half": 2,"goal_team1_half2": 3,"goal_team2_half2": 4,"shots_team1_half": 3,"shots_team1_half2": 6,"shots_team2_half": 34,"shots_team2_half2": 2,"shots_on_target_half": 3,"shots_on_target_half2": 2,"offsides_half": 3,"offsides_half2": 4,"corners_half": 3,"corners_half2": 3,"tackels_half": 3,"tackels_half2": 3,"cycle": 3,"home_or_away": "home","goals": [],"assist": [],"createdAt": "2019-11-08T05:43:09.242Z","updatedAt": "2019-11-08T05:43:09.242Z","__v": 0
}

请帮助我理解为什么Match输出中的玩家数组为空，谢谢