mongoose mongodb code example

Example 1: how to install mongoose

$ npm install mongoose

Example 2: mongoose setup

// getting-started.js
const mongoose = require('mongoose');
mongoose.connect("mongodb://localhost:27017/name", { useUnifiedTopology: true, useNewUrlParser: true });

Example 3: mongoose

import express from 'express';
or
const exporess = require('express');
import mongoose from 'mongoose';
or
const mongoose = require('mongoose');
const app = express();
mongoose.connect('mongodb://localhost:27017/mongo-tree' , {
    useNewUrlParser: true,
    useUnifiedTopology: true
});

const db = mongoose.connection;
db.on('error', console.error.bind(console, 'connection error:'));
db.once('open', function() {
console.log('connected db')
});
app.use('/', (req, res) => {
    res.send('hello');
}
);
const port = process.env.PORT || 5000
app.listen(port, () => {
console.log('running');
})
//for es6 >npm i @babel/core @babel/node @babel/preset-env --save-dev

//create  .babelrc file and put this 
{
    "presets": [
        "@babel/preset-env"
    ]
}
//and package.json
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1",
    "start": "nodemon --exec babel-node server"
  },

Example 4: mongoose node js

// getting-started.js
var mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test', {useNewUrlParser: true});

Example 5: mongoose collection relation

const mongoose = require('mongoose');

const personSchema = mongoose.Schema({
  _id: Schema.Types.ObjectId,
  name: String,
  age: Number,
  stories: [{ type: Schema.Types.ObjectId, ref: 'Story' }]
});

const storySchema = mongoose.Schema({
  author: { type: Schema.Types.ObjectId, ref: 'Person' },
  title: String,
  fans: [{ type: Schema.Types.ObjectId, ref: 'Person' }]
});

const Story = mongoose.model('Story', storySchema);
const Person = mongoose.model('Person', personSchema);

Story.
  findOne({ title: 'Casino Royale' }).
  populate('author').
  exec(function (err, story) {
    if (err) return handleError(err);
    console.log('The author is %s', story.author.name);
    // prints "The author is Ian Fleming"
  });

Example 6: mongoose

const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost:27017/test', {useNewUrlParser: true, useUnifiedTopology: true});

const Cat = mongoose.model('Cat', { name: String });

const kitty = new Cat({ name: 'Zildjian' });
kitty.save().then(() => console.log('meow'));