NodeJS-猫鼬，子文档对象没有方法.id（）或.create（）

Question

I am trying to insert a subdocument using .create() and also query said document using .id(). I've been following the guide here

I am getting the error: object has no method 'id()' or 'create()'

The following is my code:

/db/schemas/AnnouncementsSchema.js

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


var postSchema = new Schema({
    title: String,
    dateCreated: String,
    dateEdited: { type: Date, default: Date.now() },
    summary: String,
    body: String
});

var announcementsSchema= new Schema({
    categoryName: String,
    posts: [postSchema]
});

announcementsSchema.methods.Update = function (callback) {
    console.log('Updating object: ' + this);

    this.save(function (err, object) {
        callback(err, object);
    });
}

var announcements = mongoose.model('announcements', announcementsSchema);
var post = mongoose.model('post', postSchema);

module.exports = {
    announcements: announcements,
    post: post
};

/routes/Announcements.js

var mongoose = require('mongoose');
var announcementsSchema = require('../../db/schemas/AnnouncementsSchema.js');

exports.InsertPost = function (req, res) {

    var announcements = announcementsSchema.announcements;
    var post =  announcementsSchema.post;

    var categoryToEdit = req.body.categoryToEdit;
    var newPost = req.body.newPost;

    announcements.GetById(categoryToEdit._id, function (err, announcment) {

        var postToAdd = new post(newPost);

        announcment.posts.create(postToAdd);

        announcment.Update(function (err, object) {
            res.send({ err: err, data: object});
        });
    });

}

I have the .save method wrapped so I can add extra functionality if needed. I crashes when it calls .create(). The same is true if I am trying to remove a post as well. Here is the code for that:

exports.DeletePost = function (req, res) {

    var announcements = announcementsSchema.announcements;

    var categoryId = req.body.categoryId;
    var postId = req.body.postId;

    announcements.findById(categoryId, function (err, object) {

        var postToDelete = object.posts.id(postId);

        console.log(postToDelete);

        res.end();
    });

}

Either way they both crash and google is pretty slim on answers. Most people have given a of different ways to expose the schemas and models, and what I have above is pretty much a sum of what they suggested. Any ideas? Thanks!

Answer 1

I found the answer after toying with this forever. It was simple. The order in which you declare your schema matters. So I had to declare my subdocument schema before I declare my parent schema. Such as:

var announcementsSchema= new Schema({
    categoryName: String,
    posts: [postSchema]
});

var postSchema = new Schema({
    title: String,
    dateCreated: String,
    dateEdited: { type: Date, default: Date.now() },
    summary: String,
    body: String
});

This worked! I am now able to keep all the rest of the code the same, but now the methods exist!

Answer 2

Even if I recently picked up Express.js, I will do my best in trying to provide a useful answer. Hope it helps!

If you want to access the id of a particular post, it is stored in the ._id property, not id . Moreover, I believe that you first have to loop over object.posts since it is an array of posts:

exports.DeletePost = function (req, res) {

    var announcements = announcementsSchema.announcements;

    var announcementId = req.body.announcementId;
    var postId = req.body.postId; // This is the _id property of an element contained within the posts array
    var postToDelete = {};

    announcements.findById(announcementId, function (err, object) {

        // Get the posts array
        var posts = object.posts;

        // Loop over it until you find the post with the id that you stored in postId
        for (var i = 0; i < posts.length; i ++) {
           if (posts[i]._id == postId) {
               postToDelete = posts[i];
           }
        }

        console.log(postToDelete);

        res.end();
    });

}

As for your InsertPost function, you should also take into account the fact that posts is an array. Hence, you could simply push the new post into that array and save it accordingly:

exports.InsertPost = function (req, res) {

    var announcements = announcementsSchema.announcements;
    var post =  announcementsSchema.post;

    var announcementId = req.body.announcementId; 

    var newPost = req.body.newPost;

    announcements.findById(announcementId, function (err, announcment) {

        var postToAdd = new post(newPost);

        announcment.posts.push(postToAdd);

        announcment.save(function(err) {
           if (err) {
               res.send(500, { error: err.stack });
           }

           console.log('Success');

           res.end();
        });
    });

}