node-js-coding-challenge: A JavaScript repository from GeorgePadmore

Vien Health Node coding challenge

Stack:

Node.js
MongoDB

Installation

Follow these steps to install and run the application:

Clone the repo:

git clone --depth 1 https://github.com/GeorgePadmore/node-js-coding-challenge
cd node-js-coding-challenge

Install the dependencies:

npm install

Set the environment variables:

nano .env

# open .env and modify the environment variables (if needed)

Features
Commands
Environment Variables
Project Structure
Error Handling
Validation
Authentication

Features

NoSQL database: MongoDB object data modeling using Mongoose
Authentication and authorization: using passport
Validation: request data validation using Joi
Logging: using winston and morgan
Testing: unit and integration tests using Mocha
Error handling: centralized error handling mechanism
Dependency management: with [npm]
Environment variables: using dotenv and cross-env
Security: set security HTTP headers using helmet
Santizing: sanitize request data against xss and query injection
CORS: Cross-Origin Resource-Sharing enabled using cors
Compression: gzip compression with compression
Git hooks: with husky and lint-staged
Linting: with ESLint and Prettier
Editor config: consistent editor configuration using EditorConfig

Commands

Running locally:

npm run start

Testing:

# run all tests
npm run test

Environment Variables

The environment variables can be found and modified in the .env file. They come with these default values:

# Port number
PORT=3000

# URL of the Mongo DB
MONGODB_URL=mongodb://127.0.0.1:27017/database_name

# JWT
# JWT secret key
JWT_SECRET=yoursamplesecretgoeshere
# Number of minutes after which an access token expires
JWT_ACCESS_EXPIRATION_MINUTES=30
# Number of days after which a refresh token expires
JWT_REFRESH_EXPIRATION_DAYS=30

Project Structure

app_backend\
 |--config\         # Environment variables and configuration related things
 |--controllers\    # Route controllers (controller layer)
 |--middlewares\    # Custom express middlewares
 |--models\         # Mongoose models (data layer)
 |--routes\         # Routes
 |--services\       # Business logic (service layer)
 |--utils\          # Utility classes and functions
 |--validations\    # Request data validation schemas
 |--app.js          # Express app
 |--index.js        # App entry point

API Endpoints

List of available routes:

Auth routes:
POST /api/register - register
POST /api/login - login
POST /api/refresh-tokens - refresh auth tokens\

User/Profile routes:
POST /api/profile - Get Profile details of user\

Error Handling

The app has a centralized error handling mechanism.

Controllers should try to catch the errors and forward them to the error handling middleware (by calling next(error)). For convenience, you can also wrap the controller inside the catchAsync utility wrapper, which forwards the error.

const catchAsync = require('../utils/catchAsync');

const controller = catchAsync(async (req, res) => {
  // this error will be forwarded to the error handling middleware
  throw new Error('Something wrong happened');
});

The error handling middleware sends an error response, which has the following format:

{
  "code": 404,
  "message": "Not found"
}

When running in development mode, the error response also contains the error stack.

The app has a utility ApiError class to which you can attach a response code and a message, and then throw it from anywhere (catchAsync will catch it).

For example, if you are trying to get a user from the DB who is not found, and you want to send a 404 error, the code should look something like:

const httpStatus = require('http-status');
const ApiError = require('../utils/ApiError');
const User = require('../models/User');

const getUser = async (userId) => {
  const user = await User.findById(userId);
  if (!user) {
    throw new ApiError(httpStatus.NOT_FOUND, 'User not found');
  }
};

Validation

Request data is validated using Joi. Check the documentation for more details on how to write Joi validation schemas.

The validation schemas are defined in the src/validations directory and are used in the routes by providing them as parameters to the validate middleware.

const express = require('express');
const validate = require('../../middlewares/validate');
const userValidation = require('../../validations/user.validation');
const userController = require('../../controllers/user.controller');

const router = express.Router();

router.post('/users', validate(userValidation.createUser), userController.createUser);

Authentication

To require authentication for certain routes, you can use the auth middleware.

const express = require('express');
const auth = require('../../middlewares/auth');
const userController = require('../../controllers/user.controller');

const router = express.Router();

router.post('/users', auth(), userController.createUser);

These routes require a valid JWT access token in the Authorization request header using the Bearer schema. If the request does not contain a valid access token, an Unauthorized (401) error is thrown.

Generating Access Tokens:

An access token can be generated by making a successful call to the register (POST /api/register) or login (POST /api/login) endpoints. The response of these endpoints also contains refresh tokens (explained below).

An access token is valid for 30 minutes. You can modify this expiration time by changing the JWT_ACCESS_EXPIRATION_MINUTES environment variable in the .env file.

Refreshing Access Tokens:

After the access token expires, a new access token can be generated, by making a call to the refresh token endpoint (POST /api/refresh-tokens) and sending along a valid refresh token in the request body. This call returns a new access token and a new refresh token.

A refresh token is valid for 30 days. You can modify this expiration time by changing the JWT_REFRESH_EXPIRATION_DAYS environment variable in the .env file.

GeorgePadmore/node-js-coding-challenge