Mongoose Scripts

aliasIssue.js

const { Schema, model, connect } = require("mongoose");

connect('mongodb://localhost:27017/test', { useNewUrlParser: true, useCreateIndex: true }, (err) => {
    if (!err) {
        console.log('MongoDB Connection Succeeded.');
    } else {
        console.log('Error in DB connection: ' + err);
    }
});

const trial = new Schema({
    a: {
        b1: { alias: 'b.first', type: String },
        b2: { alias: 'b.second', type: String}
    }
});
trial.virtual('boss').get(function(){return this.b})

//NOTE -> COMMENT THE ABOVE AND UNCOMMENT THIS, TO USE THE NEW SCHEMA
// const trial = new Schema({
//     a: {
//         alias: 'boss',   //TypeError: Invalid schema configuration: `Boss` is not a valid type at path `a.alias`. See http://bit.ly/mongoose-schematypes for a list of valid schema types.
//         b1: { alias: 'b.first', type: String },
//         b2: { alias: 'b.second', type: String}
//     }
// });

const trialModel = model( 'trial', trial);

let data = {
    a: 'Hi',
    b: {
        b1: 'First',
        b2: 'Second'
    }
}

let doc;
trialModel.create(data)
    .then(newDoc => {     doc = newDoc;     console.log(newDoc.boss.joiner);    })
    .catch(err => console.log(err.code))

duplicateKeyIssue.js

/*
Run the script... duplicates won't be created
GET /post ...     duplicates won't be created
GET /delete, then GET /post...  DUPLICATES CREATED

Just looking at console output is enough to get if there is a problem
*/

const express = require('express')
const app = express()
const { Schema, Types, connect, model, connection } = require('mongoose')


connect('mongodb://localhost/DUPLICATE15', {useNewUrlParser: true, useUnifiedTopology: true, useCreateIndex: true})
    .then(val => console.log('Connected to mongo'))
    .catch(err => console.error('❗❗ Couldn\'t establish connection to MongoDB'))

connection
    .on('error', err => console.log(err.code) )    
    .once('open', () => console.log('💠 Open to connection') )

    //CATEGORY
const categorySchema = new Schema({
    name: {
        type: String,
        unique: true,
    },
    todoIds: {
        type: [Types.ObjectId],
    }
})
const categoryModel = model('categories', categorySchema)

const todoSchema = new Schema({
    title: String,
    category: String,
})
todoSchema.post('save', async function(doc){

    //@ISSUE - Two categories with same name, are being created, even though name should be unique
    await categoryModel.findOne({name: doc.category}, async (err, catDoc) => {
        if(err){    return console.log('Error while getting', 'Collection: category', 'Path: todoPostSave')   }
        else if(!catDoc){
            console.log('ℹ Going to create collection with name: ', doc.category)
            if(categoryModel.countDocuments({name: doc.category}, (err, count) => { //[DEBUG]   For debugging purpose
                if(err){    console.log('Error in counting')    }
                console.log(`{name: ${doc.category}}  count =`, count)
            }))
            categoryModel.create({  //async... not using await here
                name: doc.category,
                todoIds: [doc._id]
            }).then((addedCatDoc) => {
                console.log('🎉 Created category: ', addedCatDoc.name);
            })
            .catch(err => console.error('ERROR in creating category ', err.code == 11000 ? 'DuplicateKey': ''))
        }
    })
})

const todoModel = model('todos', todoSchema)



let todos = [
    { title: 't1', category: 'something' },
    { title: 't2', category: 'something' },
    { title: 't3', category: 'something' }
]

// THE CODE OUTSIDE ANY REQUEST HANDLER - begin

let todo2 = [{ title: 'sec1', category: 'trial'},{ title: 'sec2', category: 'trial' }]
todoModel.create(todo2, (err, docs) => {
    if(err){
        return console.log('! Error while creating todo ', err.code);
    }
    console.log('All todos were added successfully')
})

// THE CODE OUTSIDE ANY REQUEST HANDLER - end


app.use(express.json());
app.use(express.urlencoded({ extended: false }));

app.get('/post', (req, res) => {
    console.log('received post request');
    todoModel.create(todos, (err, docs) => {
        if(err){
            return res.status(500).send('! Error while creating todo ', err.code);
        }
        res.send('All todos were added successfully')
    })
})

app.get('/delete', async (req, res) => {
    console.log('received deleteAll request');
    await connection.dropDatabase()    
    
    res.send('Done');
})

app.get('/', async (req, res) => {
    console.log('received getCategories request');
    await categoryModel.find({}, (err, docs) => {
        if(err) return res.sendStatus(500)
        res.send(docs)
    })
})

const PORT = process.env.PORT || 3000
app.listen(PORT, () => {console.log(`listening on port ${PORT}....`)})