How do I save a object to custom collection? - node.js

Question

Sorry if I have mixed up the terminology, but I am trying to understand how I can save objects to custom collections dynamically. If I have a app that handles blogs I can only save my blogs to "/My-app/Blogs"
I want to be able to choose a sub-collection dynamically when saving like "/My-app/Good_blogs/Blogs" or "/My-app/Bad_blogs/Blogs"
This is my current code:
app.js
const express = require('express')
const mongoose = require('mongoose')
const app = express()
app.use(express.urlencoded({ extended: true }))
app.use(express.json());
require('dotenv/config')
//Import Routes
const blogRoute = require('./routes/blogs')
app.use('/blogs', blogRoute)
//Connect to DB
mongoose.connect(process.env.MONGOOSE_CONNECT, { useUnifiedTopology: true, useNewUrlParser: true },
() => console.log("Connected to MongoDB"))
app.listen(3000)
Blog.js (Schema)
const mongoose = require('mongoose')
const BlogSchema = mongoose.Schema({
message: String,
})
module.exports = mongoose.model('Blog', BlogSchema)
blogs.js
const express = require('express')
const router = express.Router()
const Blog= require('../models/Blog')
router.post('/', async(req, res) => {
const blog = new Blog(req.body)
await blog.save()
res.sendStatus(200)
})
module.exports = router

Answer 1

From our comments I have deduced you are trying to add documents to a collection whose name is provided in a string. It is not recommended to have multiple collections with the same schema. What you should do is put all your blog posts in one big collection and add a property to query it by that will give you the posts you want.

Answer 2

There is no such thing as a "sub-collection", but you can make a property of type array and store more documents in it.
You can use a schema like so:
const BlogSchema = mongoose.Schema({
message: String,
});
BlogSchema.add({subBlogs: [{type: mongoose.Schema.Types.ObjectID, ref: BlogSchema }]});
The subBlogs property just needs to be added after creation because BlogSchema is undefined until after creation.
subBlogs will now be an array of blog _ids, to which you can push new blogs into, and populate using Mongoose as you would populate any other data.