尝试加入两个文档时无法在 Mongoose 中填充路径

Question

MongooseError：无法填充路径 loaned_to，因为它不在您的模式中。将 strictPopulate 选项设置为 false 以覆盖。

我尝试在 mongodb 中使用 mongoose 在 nodejs 中加入两个文档，但不幸的是出现了这个错误。我的猫鼬版本是 6.0.6

书籍架构

const mongoose = require('mongoose');

const BookSchema = new mongoose.Schema({
    "name": {type: String, required: true},
    "author_name": {type: String, required: true},
    "published_date": {type: Date, required: false},
    "copies": [
        {
            "isbn_number": {type: String, required: true},
            "status": {type: String, required: true, default: "Available"},
            "due_back": {type: Date, required: false},
            "loaned_to": {type: mongoose.Schema.Types.ObjectId, required: false, ref: "User"}
        },
    ]
})

const Book = mongoose.model("Book", BookSchema);
module.exports = Book;

用户架构

const mongoose = require('mongoose');

const UserSchema = new mongoose.Schema({
    "first_name": {type: String, required: true},
    "last_name": {type: String, required: true},
    "phone_number": {type:  String, required: true},
    "address": {type:  String, required: false},
    "user_name":{type: String, required: true},
    "password": {type:  String, required: true},
    "email": {type:  String, required: true},
    "notifications": [
        {
            "notification_id" : {type:"string", required:true},
            "notification": {type: "string", required: true}
        },
    ]
})

const User = mongoose.model("User", UserSchema);
module.exports = User;

我的代码加入文件

exports.getAllBooks = async (req, res) => {
    try {
        let data = await BookModel.findOne().populate("loaned_to");
        res.status(200).send({data: [...data], success: true})
    } catch (err) {
        console.log(err)
        res.status(404).send({success: false, msg: err.message})
    }
}

Answer 1

exports.getAllBooks = async (req, res) => {
  try {
    let data = await BookModel.findOne().populate({
      path: 'copies.loaned_to',
      select:
        'first_name lastName phone_number address user_name email notifications',
    });
    res.status(200).json({ data: [...data], success: true });
  } catch (err) {
    console.log(err);
    res.status(500).json({ success: false, msg: err.message });
  }
};