In this section, we will explore the implementation of routers within an Express application, with a focus on modularity. Modular routing is crucial for maintaining a clean, scalable, and maintainable codebase, especially in complex applications. We will also examine various types of routers, their use cases, key considerations, and best practices.

Detailed Explanation

1. Router Initialization:

   const UserRouter = require("express").Router();:
   

   This line initializes a new router instance specifically for user-related routes, promoting separation of concerns.

2. Controller and Middleware Integration:

   The router integrates various middleware and controller functions, such as:

   checklogin allowUser setPath uploader bodyValidator

3. Exporting the Router:

   • module.exports = UserRouter;: Exports the configured router for integration with the main application router, facilitating modular architecture.

One of the key components of Express.js is its routing system, which allows you to define routes for handling different HTTP methods. Main HTTP methods (GET, POST, PUT, PATCH, DELETE) and the use method

• GET : The GET method is used to retrieve data from a server. When a client makes a GET request, it’s asking for a specific resource. This is typically used to request data from the server without making any changes to the server's data.
• POST : The POST method is used to send data to the server to create a new resource. When a client makes a POST request, it’s submitting data to be processed, like a form submission
• Put : The PUT method is used to update an existing resource on the server. When a client makes a PUT request, it’s providing data that will replace the current representation of the resource.
• PATCH : The PATCH method is used to apply partial modifications to a resource. Unlike PUT, which updates the entire resource, PATCH only updates the specified fields
• DELETE : The DELETE method is used to remove a resource from the server. When a client makes a DELETE request, it’s asking for the resource to be deleted.
• USE : The use method is a bit different from the above methods. It’s used to apply middleware functions to your application. Middleware functions are functions that have access to the request object (req), the response object (res), and the next middleware function in the application’s request-response cycle. You can also use the use method to define routes for specific paths

Complete Code: User Router

Below is an example of setting up a router for the user module in an Express application:

javascriptCopy code
const UserRouter = require("express").Router();

const userCTRL = require("./user.controller");
const checklogin = require("../../middlewares/auth.middleware");
const allowUser = require("../../middlewares/rbac.middleware");

const { setPath, uploader } = require("../../middlewares/uploader.middleware");
const { bodyValidator } = require("../../middlewares/validator.middleware");
const { UserCreateDTO } = require("./user.request");

UserRouter.route("/")
    .post(
        checklogin,
        allowUser,
        setPath('/user'),
        uploader.single('image'),
        bodyValidator(UserCreateDTO),
        userCTRL.userCreate
    )
    .get(userCTRL.getallUsers);

UserRouter.route("/:id")
    .get(userCTRL.userbyID)
    .patch(checklogin, userCTRL.updateUserById)
    .delete(checklogin, userCTRL.deleteUserById);

module.exports = UserRouter;