ValidationError：ObjectId 没有被推入数组..导致 ValidationError

Question

我是后端网络开发的新手，目前正在学习数据关联...我遇到了一个错误，这对我来说似乎很严重，因为我是这个主题的新手...我正在尝试将我的 userSchema 的 postArray 中的 Post 的 ObjectId。

当我将第一篇文章添加到特定用户时，我没有得到我所期望的结果。我本来希望将 ObjectId 推入 postArray 中，但实际发生的事情是整个 newPost 得到了推入postArray。这是遇到的第一个问题。我在这里没有得到任何错误，但我没有得到我所期望的！

第二个是当我向postArray添加另一篇文章时，它给了我一个巨大的错误，命名为ValidationError..我实际上花了几个小时试图修复这个错误，这可能是一个小错误，但对我来说是一个痛苦。下面给出了我的代码，错误也发布在下面！

var mongoose = require("mongoose");

mongoose.connect("mongodb://localhost/testdatabase");

var postSchema = new mongoose.Schema({
   title: String,
   content: String
});

var Post = mongoose.model("Post", postSchema);

var userSchema =  new mongoose.Schema({
    name: String,
    email: String,
    postArray: [{
        type: mongoose.Schema.Types.ObjectId,
        ref: 'Post'
    }]
});
var User = mongoose.model("User", userSchema);

var alex = new User({
    name: "Alexander",
    email: "[email protected]"
});

alex.save();

Post.create({
    title: "I'm terribly stuck here!",
    content: "Does anyone have an idea of where I'm stuck?"
}, function(err, newPost) {
    User.findOne({name: "Alexander"}, function(err, foundUser) {
        if(err) {
            console.log(err);
        } else {
            console.log("THE NEWLY ADDED POST IS" + newPost);
            foundUser.postArray.push(newPost);
            foundUser.save(function(err, savedData) {
                if(err) {
                    console.log(err);
                } else {
                    console.log(savedData);
                }
            });
        }
    });
});

Blackdeath:~/environment/Associations $ node references.js
  THE NEWLY ADDED POST IS{ _id: 5a5845c180a490137330bcae,
    title: 'I\'m terribly stuck here!',
    content: 'Does anyone have an idea of where I\'m stuck?',
    __v: 0 }
  { ValidationError: User validation failed: postArray: Cast to [undefined] failed for value "[{"_id":"5a5844112d4c6512beb16846","title":"This makes me sick!","content":"I\'m stuck here..Someone save me!","__v":0}]" at path "postArray"
      at MongooseError.ValidationError (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/error/validation.js:27:11)
      at model.Document.invalidate (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:1643:32)
      at _init (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:413:18)
      at init (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:381:5)
      at model.Document.$__init (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:351:3)
      at model.syncWrapper [as $__init] (/home/ec2-user/environment/Associations/node_modules/kareem/index.js:234:23)
      at model.Document.init (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:319:8)
      at completeOne (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/query.js:1980:12)
      at Immediate.<anonymous> (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/query.js:1502:11)
      at Immediate.<anonymous> (/home/ec2-user/environment/Associations/node_modules/mquery/lib/utils.js:119:16)
      at runCallback (timers.js:672:20)
      at tryOnImmediate (timers.js:645:5)
      at processImmediate [as _immediateCallback] (timers.js:617:5)
    errors: 
     { postArray: 
        { ValidatorError: Cast to [undefined] failed for value "[{"_id":"5a5844112d4c6512beb16846","title":"This makes me sick!","content":"I\'m stuck here..Someone save me!","__v":0}]" at path "postArray"
            at MongooseError.ValidatorError (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/error/validator.js:25:11)
            at _init (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:413:37)
            at init (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:381:5)
            at model.Document.$__init (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:351:3)
            at model.syncWrapper [as $__init] (/home/ec2-user/environment/Associations/node_modules/kareem/index.js:234:23)
            at model.Document.init (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/document.js:319:8)
            at completeOne (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/query.js:1980:12)
            at Immediate.<anonymous> (/home/ec2-user/environment/Associations/node_modules/mongoose/lib/query.js:1502:11)
            at Immediate.<anonymous> (/home/ec2-user/environment/Associations/node_modules/mquery/lib/utils.js:119:16)
            at runCallback (timers.js:672:20)
            at tryOnImmediate (timers.js:645:5)
            at processImmediate [as _immediateCallback] (timers.js:617:5)
          message: 'Cast to [undefined] failed for value "[{"_id":"5a5844112d4c6512beb16846","title":"This makes me sick!","content":"I\\\'m stuck here..Someone save me!","__v":0}]" at path "postArray"',
          name: 'ValidatorError',
          properties: [Object],
          kind: 'cast',
          path: 'postArray',
          value: '[{"_id":"5a5844112d4c6512beb16846","title":"This makes me sick!","content":"I\'m stuck here..Someone save me!","__v":0}]',
          reason: undefined } },
    _message: 'User validation failed',
    name: 'ValidationError' }
  

Answer 1

发现错误。我未能将 mongoose 包添加到 package.json

一开始我只是这样做

npm install mongoose

后来我尝试做

npm install mongoose --save

而且成功了！