嵌套的ObjectId填充数组

问题描述

我正在尝试populate中的array of ObjectId mongoose。在该数组内，将再次需要populate。

假设我具有User数据模式，如下所示：-

• models/User.js

  /** Dependencies */
  // Mongoose
  const mongoose = require('mongoose')
  
  /** Data Schema */
  // User Data Schema
  const UserSchema = new mongoose.Schema({
      // User's Name
      name: {
          // User's Firstname
          firstName: { type: String,required: true,min: 4 },// User's Lastname
          lastName: { type: String,min: 4 }
      },// User's Address Array[ID]
      address: [{
          // AddressID
          addressID: { type: mongoose.Schema.Types.ObjectId,ref: "Address" },}]
  })
  
  /** Data Schema Exports */
  module.exports = mongoose.model('User',UserSchema);
  

• 和Address模式models/Address.js

  /** Dependencies */
  // Mongoose
  const mongoose = require('mongoose')
  
  /** Data Schema */
  // Address Data Schema
  const AddressSchema = new mongoose.Schema({
      // Address 1
      addressOne: { type: String,required: true },// Address 2
      addressTwo: { type: String },// Postcode
      postcode: { type: String,// City
      city: { type: String,// StateID
      state: { type: mongoose.Schema.Types.ObjectId,ref: "State" },// CountryID
      country: { type: mongoose.Schema.Types.ObjectId,ref: "Country" }
  })
  
  // State Data Schema
  const StateSchema = new mongoose.Schema({
      // Gender's Name
      name: { type: String,required: true }
  })
  
  // Country Data Schema
  const CountrySchema = new mongoose.Schema({
      // Race's Name
      name: { type: String,required: true }
  })
  
  /** Data Schema Export */
  const Address = mongoose.model('Address',AddressSchema)
  const State = mongoose.model('State',StateSchema)
  const Country = mongoose.model('Country',CountrySchema)
  module.exports = {
      Address,State,Country
  }
  

我知道如何populate state country和Address，如下所示：-

Address.find()
.populate('state')
.populate('country')
.then(async address => {
    // do stuff
})
.catch(err => res.json({ err }))

但是我怎么populate的{​​{1}}数组。我做了如下所示的代码：-

ObjectId

很不幸，User.findById({ _id: userId }) // let's say I've the userId .populate('address') .then(async user => { console.log(await user) }) .catch(err => res.json({ err })) 我是这样的：-

returns

我想要得到的如下所示：-

{
    "_id": "5fabababababababababab1"
    "name": {
        "firstName": "Lalapolalaa","lastName": "Newb"
    },"address": [
        {
            "_id": "5fcdcdcdcdcdcdcdcdc1","addressID": "5fefefefefefefefefef1" // should've populate (but not working)
        }
    ],"__v": 0   
}

如何通过下面的当前代码获取该信息（如上所示）：-

{
    "_id": "5fabababababababababab1"
    "name": {
        "firstName": "Lalapolalaa","addressID": { // populate happens here
                "_id": "5fefefefefefefefefef1","addressOne": "Lot 1,Street 12","addressTwo": "SS 21","postcode" : "47500","city": "Subang Jaya","state": { // populate happens here
                    "_id": "5fghghghghghghghghg1","name": "Selangor","__v": 0
                },"country": { // populate happens here
                    "_id": "5ijijijijijijijijij1","name": "Malaysia","__v": 0
                }
                "__v": 0
            }
        }
    ],"__v": 0   
}

解决方法

我可以通过以下更正找到自己的解决方案：-

• 在models/User.js中：-

/** Dependencies */
// Mongoose
const mongoose = require('mongoose')

/** Data Schema */
// User Data Schema
const UserSchema = new mongoose.Schema({
    // User's Name
    name: {
        // User's Firstname
        firstName: { type: String,required: true,min: 4 },// User's Lastname
        lastName: { type: String,min: 4 }
    },// User's Address Array[ID]
    address: [{ type: mongoose.Schema.Types.ObjectId,ref: "Address" }] // 1st Correction
})

/** Data Schema Exports */
module.exports = mongoose.model('User',UserSchema);

然后接下来，我可以直接进行如下所示的代码（解决方案）：-

User.findById({ _id: userId }) // let's say I've the userId
.populate('address') // assuming this populate of address works
.then(async user => {
    // create an array to hold JUST the IDs of Address available
    let addressesID = []
    // transfer all Address's ID
    for(let i = 0; i < (user.address).length; i++) {
        // push available address's ID one by one
        addressesID.push(user.address[i]._id)
    }
    // get all address info available in Address (from DB) 
    const addresses = await Address.find(
        { _id: { $in: addressesID } }
    )
    .populate('state')
    .populate('country')
    .then(address => address)
})
.then(all => console.log(all))
.catch(err => res.json({ err }))

然后它将console.log()

{
    _id: '5fabababababababababab1',name: {
        firstName: 'Lalapolalaa',lastName: 'Newb'
    },address: { // populate happens here
        _id: '5fefefefefefefefefef1',addressOne: 'Lot 1,Street 12',addressTwo: 'SS 21',postcode" : '47500',city: 'Subang Jaya',state: { // populate happens here
            _id: '5fghghghghghghghghg1',name: 'Selangor',__v: 0
        },country: { // populate happens here
            _id: '5ijijijijijijijijij1',name: 'Malaysia',__v: 0
    },__v: 0
}