16.9. Creating a CRUD with NodeJS and MongoDB: Validation of received data

To begin with, CRUD is an acronym for the basic operations we can perform on any database: Create, Read, Update, and Delete. In this chapter, we'll explore how to create a CRUD using NodeJS and MongoDB, and in particular, we'll focus on validating incoming data.

Why is data validation important?

Data validation is a crucial step in the development of any application. It ensures that the data we are receiving is of the type and format that we expect. This is important for several reasons. First, it helps protect our database from malicious or corrupted data. Second, it helps maintain data consistency, which is crucial to database integrity. Third, it can improve the user experience by providing helpful feedback when data entered is invalid.

Setting up the NodeJS and MongoDB environment

First, we need to set up our development environment. This involves installing NodeJS and MongoDB on our system. After installation, we can start a new NodeJS project and install the necessary packages. For this tutorial, we will need the express, mongoose, and joi packages.

Creating the Data Model

We will use mongoose to create our data model. mongoose is a tool that facilitates interaction with MongoDB from within NodeJS. It allows us to define the structure of our data using schemas. Here is an example of how we can define a schema for a user:

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

const UserSchema = new Schema({
  name: {
    type: String,
    required: true
  },
  email: {
    type: String,
    required: true,
    unique: true
  },
  password: {
    type: String,
    required: true
  }
});

module.exports = mongoose.model('User', UserSchema);

Data validation with Joi

Joi is a powerful and flexible data validation library for JavaScript. It allows us to define validation schemes with a clear and concise syntax. Here is an example of how we can use Joi to validate input data for our user model:

const Joi = require('joi');

const UserValidationSchema = Joi.object({
  name: Joi.string().required(),
  email: Joi.string().email().required(),
  password: Joi.string().min(8).required()
});

module.exports = UserValidationSchema;

Integrating data validation into our routes

Now that we have our data validation set up, we can integrate it into our routes. Here is an example of how we can do this for the user creation route:

const express = require('express');
const router = express.Router();
const User = require('../models/User');
const UserValidationSchema = require('../validation/UserValidationSchema');

router.post('/', async (req, res) => {
  const { error } = UserValidationSchema.validate(req.body);
  
  if (error) {
    return res.status(400).send(error.details[0].message);
  }

  const user = new User(req.body);
  await user.save();
  
  res.send(user);
});

module.exports = router;

In this example, we first validate the input data using our validation scheme. If validation fails, we return a 400 error with the error message. If the validation is successful, we proceed with creating the user.

Conclusion

Data validation is a crucial step in the development of any application. It helps protect our database, maintain data consistency, and improve the user experience. In this chapter, we explore how to create a CRUD with NodeJS and MongoDB and how to integrate data validation into our routes using Joi.