Mongoose 不在数组的 objectid 中填充 objectid

Question

这个问题有点长。所以我为你粗体输入了关键信息。

我开发了一个类似 stackoverflow 的项目。我有 4 个数据库：

• 问题
• 用户
• 解决方案
• cmets

我互相引用了这些架构。这是架构：

问题架构

const problemSchema = new mongoose.Schema({
    title: {
        type: String,
        required: [true, 'You have to enter a title']
    },
    content: {
        type: String,
        required: [true, 'You have to enter a content']
    },
    createdAt: {
        type: Date,
        default: Date.now()
    },
    slug: {
        type: String
    },
    solution: [
        {
            type: mongoose.Schema.Types.ObjectId,
            ref: 'Solution'
        },
    ],
    comment: [
        {
            type: mongoose.Schema.Types.ObjectId,
            ref: 'Comment'
        }
    ],
    votes: {
        type: Number,
        default: 0
    },
    views: {
        type: Number,
        default: 0
    },
    user: {
        type: mongoose.Schema.Types.ObjectId,
        required: true,
        ref: 'User'
    }
})

module.exports = mongoose.model('Problem', problemSchema)

用户架构：

const userSchema = new mongoose.Schema({


    name: {
        type: String,
        required: true
    },
    email: {
        type: String,
        required: [true, 'You have to enter an email'],
        unique: true,
        match: [
            /^([\w-\.]+@([\w-]+\.)+[\w-]{2,4})?$/,
            'Please provide a valid email address.'
        ]
    },
    password: {
        type: String,
        required: [true, 'You have to enter a password'],
        minlength: [6, 'Your password cannot be less than 6 character.'],
        select: false
    },
    role: {
        type: String,
        default: 'user',
        enum: ['user', 'admin']
    },
    createdAt: {
        type: Date,
        default: Date.now()
    },
    about: {
        type: String
    },
    place: {
        type: String
    },
    age: {
        type: Number
    },
    blocked: {
        type: Boolean,
        default: false
    },
    problem: [
        {
            type: mongoose.Schema.Types.ObjectId,
            ref: 'Problem'
        },
    ],
    solution: [
        {
            type: mongoose.Schema.Types.ObjectId,
            ref: 'Solution'
        }
    ],
    comment: [
        {
            type: mongoose.Schema.Types.ObjectId,
            ref: 'Comment'
        }
    ]
})

和评论架构：

const commentSchema = new mongoose.Schema({
    content: {
        type: String,
        required: [true, 'You have to enter a content']
    },
    createdAt: {
        type: Date,
        default: Date.now()
    },
    isFunctional: {
        type: Boolean,
        default: false
    },
    user: {
        type: mongoose.Schema.Types.ObjectId,
        required: true,
        ref: 'User'
    },
    problem: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'Problem'
    },
})


module.exports = mongoose.model('Comment', commentSchema)

在我的项目中，我将问题发送到 MongoDB。然后我发送评论。保存 cmets 后，我将这些 cmets 添加到问题和用户数据库中。

cmet 保存在 DB 中的函数：

const Comment = require('../models/comment/Comment')
const Problem = require('../models/problem/Problem')
const User = require('../models/user/User')
const asyncErrorWrapper = require('express-async-handler')

const addCommentToProblem = asyncErrorWrapper(async (req, res, next) => {

    const {content, problemId} = req.body
    
    const newComment = await Comment.create({
        content: content,
        problem: problemId,
        user: req.user.id,
    })

    const problemOfComment = await Problem.findByIdAndUpdate(problemId, {
        $push: { comment: newComment._id }
    })

    const userOfComment = await User.findByIdAndUpdate(req.user.id, {
        $push: { comment: newComment._id }
    })

})

好吧，到目前为止一切都很好。问题来了。当我尝试解决问题时，我会填充一些字段，例如用户字段。所以我可以在这个问题的细节中添加用户信息。在问题模式中填充用户和评论时，它会向我发送数据。不过，我们还好。但是当我尝试在 cmets 中获取用户字段时，它不会填充用户。它只是用户信息的objectId。

这是我遇到问题的功能：

const getAProblem = asyncErrorWrapper(async (req, res, next) => {

    const {id} = req.params

    const problems = null

    await Problem.findByIdAndUpdate(id, {
        $inc: { views: 1 }
    }, { new: true })
    .populate('user') ==> THIS LINE WORKS
    .populate('comment') ==> THIS LINE WORKS
    .populate('comment.user') ==> THIS LINE DOES NOT WORK
    .exec(function(err, post) {
        if(err) {
            console.log(err)
        }
        
        res
        .status(200)
        .json({
            success: true,
            data: post
        })
    });

})

感谢您的阅读和耐心。任何帮助将不胜感激。

Answer 1

请参阅https://mongoosejs.com/docs/populate.html 的文档

然后试试这个方法。

const getAProblem = asyncErrorWrapper(async (req, res, next) => {

const {id} = req.params

const problems = null

await Problem.findByIdAndUpdate(id, {
    $inc: { views: 1 }
}, { new: true })
.populate('user') ==> THIS LINE WORKS
.populate({
   'path': 'comment',
   'populate': {
     'path':'user'
   }
})
.exec(function(err, post) {
    if(err) {
        console.log(err)
    }
    
    res
    .status(200)
    .json({
        success: true,
        data: post
    })
});
})