我有一个events模型，其中guests可以“注册”并加入活动。每个活动都是一场竞赛，因此每个活动都有最大数量的“客人”，因为某些插槽被标记为“获胜者”。为了确保奖品在访客注册期间不会分配过多，我想在创建活动时预构建嵌入式guests数组。
然而，当这样做时，我收到了强制转换错误Cast to ObjectId failed for value "{}" (type Object) at path "guests"，因为我还没有每个客户机的objectIds...
这是通过设计实现的，因为占位符是用“赢家”或“输家”状态构建的，因此客人可以在他们注册并插入阵列时立即得到通知。
有没有一种方法可以让我的events模型引用guests并仍然控制：
1.获奖人数
1.在每位客人注册时提供即时反馈（赢家/输家）

Event.js

const eventSchema = new Schema({
  qr_name: {
    type: String,
    required: [true, 'Enter a name for your QR code'],
  },
  event_name: String,
  location_name: String,
  description: String,
  conversions: [ conversionsSchema ],
  image: [ImageSchema],
  address: String,
  geometry: {
    type: {
      type: String,
      enum: ['Point'],
    },
    coordinates: {
      type: [Number],
    }
  },
  user: {
    type: Schema.Types.ObjectId,
    ref: 'User'
  },
  qr: {
    type: Schema.Types.ObjectId,
    ref: 'Qr'
  },
  guests: [
    {
      type: Schema.Types.ObjectId,
      ref: 'Guest',
      default: null,
    },
    {
      giveaway_interest: {
        type: String,
      },
      redeemed: {
        type: String,
        default: "No",
        date: {
          type: Date,
          default: Date.now,
        },
        updatedBy: String,
        comments: String,
      },
      notified: {
        type: String,
        default: "No",
        date: {
          type: Date,
          default: Date.now,
        },
      },
      winner: {
        type: Boolean,
        default: 0,
      },
    },
  ],
  created: {
    type: Date,  // Captures both date and time
    default: Date.now
  },
  event_start: {
    type: Date,
    required: [true, 'Date & time of event start required']
  },
  event_end: {
    type: Date,
    required: [true, 'Date & time of event end required']
  },
}, opts);

Guest.js

const mongoose = require('mongoose');
const Schema = mongoose.Schema;

const guestSchema = new Schema({
    email: {
        type: String,
        default: null
    },
    firstName: {
        type: String,
        default: null
    },
    lastName: { 
        type: String,
        default: null
    },
    age: {
        type: Number,
        default: 0
    },
    gender: {
        type: String,
        enum: ['m', 'f'],
        default: null
    },
    phone: {
        type: Number,
        default: 0
    },
    zip: {
        type: Number,
        default: 0
    },
    dateAdded: {
        type: Date,
        default: Date.now
    },
    event: {
        type: Schema.Types.ObjectId,
        ref: 'Event',
        attended: String
    },
    user: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User',
        required: true
    }
});