Also, the "Inversion Of Control" principle, which is a very useful design principle, has been used here.

This is a response from ChatGPT

Inversion of Control (IoC) is a design principle that allows a component to receive its dependencies, rather than creating them itself. This separates the concerns of creating and managing dependencies from the component that uses them, and allows for greater flexibility and testability.

There are two main types of IoC:

Dependency Injection (DI): This is the process of providing an object with its dependencies. 
                           The object doesn't create or look up its dependencies, but instead they are passed to it.

Service Locator: An object that "locates" or retrieves other objects, 
                 often used to decouple a class from the process of creating its dependencies.

Inversify is a popular library for implementing IoC in JavaScript and TypeScript projects, it uses a modular approach to build a lightweight and powerful inversion of control container for JavaScript & Node.js applications.

Inversion of control is often used in software development to increase flexibility and testability of the code. By using IoC, it is possible to change the behavior of a component by replacing its dependencies without modifying the component itself. This makes it easier to test components in isolation and to change the implementation of a component without affecting the rest of the system.

The inversify library has been used to implement an IOC container on a node express server

Full Stack Project Backend system requires Node.js v16+ to run.

Install the dependencies and devDependencies and start the server.

cd Full Stack Project Backend
npm install

Add the following environment variables in the .env file:

  MONGO_USER=<MongoDb Username>
  MONGO_PASSWORD=<MongoDb Password>
  MONGO_PATH=cluster0.6pjjs4p.mongodb.net/<atless db name>?retryWrites=true&w=majority
  PORT=<PORT Number>
  JWT_SECRET=<my-secret>
  ORIGIN_URL=<http://localhost:4200>

To run the application in the development environment:

npm dev

To run ESLint code analysis:

npm lint

To run the test cases:

npm test

To build the application:

npm build

To run the built application:

npm start

Full Stack Project Backend is very easy to install and deploy in a Docker container.

By default, the Docker will expose port 8080, so change this within the Dockerfile if necessary. When ready, simply use the Dockerfile to build the image.

cd Full Stack Project Backend
sudo docker build -t my-app .
sudo docker run -p 4000:4000 my-app

BASE_URL/api/user [Method: POST]

Add User (sample request)

    http://localhost:4000/api/user

    {
        "firstName": "Malaka",
        "lastName": "Jayakodi",
        "username": "rootx",
        "email": "[email protected]",
        "address": "Kuliyapitiya",
        "password": "123456",
        "phoneNumber": "07771234567"
    }

BASE_URL/api/user/login [Method: POST]

Login (sample request)

    http://localhost:4000/api/user/login

    {
        "username": "rootx",
        "password": "123456"
    }

BASE_URL/api/user [Method: GET]

Check user is logged (sample request)

   http://localhost:4000/api/user

BASE_URL/api/user/:userId [Method: GET]

Get User By Id (sample request)

   http://localhost:4000/api/user/63e0a78a8b31416179ac08d0

BASE_URL/api/user/:email [Method: DELETE]

Delete user by email (sample request)

  http://localhost:4000/api/user/[email protected]