Step by step guide to connecting and interacting with mongo db

mongo-mongoose.md

Mongo, Mongoose

• Install mongoose - npm install mongoose
• Create connection in app.js using your db credentials

// app.js
const mongoose = require('mongoose');

mongoose
  .connect('mongodb://localhost/my_database')
  .then(() => {
    app.listen(PORT || 3000);
  })
  .catch((error) => {
    console.log(error);
  });

• Place you DB secrets in a a nodemon.json, .env or similar file and use the process.env to pass your credentials. Don't forget to add the file with your secrets in .gitignore.

• Create models folder in the root of your project.

• Add your resource model. If your resource is Product for example, your model might look like:

  // models/product.js
  const { Schema, model } = require('mongoose');
  
  const productSchema = new Schema({
    name: { type: String, required: true },
    price: { type: Number, required: true },
  });
  
  module.exports = model('Product', productSchema);

• If you create a model that has a relation with another resource, you should link them. Take a resource Order for example, related to Product:

  // models/order.js
  const { Schema, Types, model } = require('mongoose');
  
  const orderSchema = new Schema({
    quantity: { type: Number, required: true },
    product: { type: Types.ObjectId, required: true, ref: 'Product' },
  });
  
  module.exports = model('Order', orderSchema);

  If the relationship is with a multiple documents of the other model it should be defined as follows:

  const orderSchema = new Schema({
    products: [{ type: Types.ObjectId, required: true, ref: 'Product' }],
  });

• After your model is defined you can use it to interact with your DB.

  // routes/products.js
  
  ...
  
  const Product = require('../models/product');
  
  // Get all products
  router.get('/', async (req, res, next) => {
    try {
      const products = await Product.find();
      res.status(200).json({ message: 'Get all products', products });
    } catch (error) {
      console.log(error);
      next(createError(502, error.message));
    }
  });
  
  // Create new product
  router.post('/', async (req, res, next) => {
    const { name, price } = req.body;
    const product = new Product({
      name,
      price,
    });
  
    try {
      await product.save();
      res.status(201).json({ message: 'Created a new product', product });
    } catch (error) {
      console.log(error);
      next(createError(502, error.message));
    }
  });