How to dynamically call router functions in Node.js?

Node.js is an advanced JavaScript runtime used significantly for server-side application development. In this system, the express framework is a key player among the components, which make it easy to handle HTTP requests and responses. Keeping track of routes can be quite challenging as applications grow dynamically. However, adopting dynamic routing in Node.js can be a strong approach towards this issue, where the router function is called dynamically based on runtime parameters rather than explicit definition within the code.

This method enables the server to deal with many such similar requests without having separate functions created for each individual one during coding time. An explicit generation process without having to define routes is dynamic routing. It can be more flexible and more scalable, which is especially important in large applications. With dynamic routing, we can load routes according to certain criteria or even create them on the fly from external sources, such as databases or configuration files.

Dynamic Routing:

Dynamic routing is highly advantageous due to this reason. It enables us to load routes based on specific criteria or generate them from external sources like databases or configuration files.

In Express, we can dynamically call a router function using the app.METHOD() function, where METHOD is the request's HTTP method (e.g., GET, POST, PUT, DELETE, etc.). It allows us to handle requests dynamically without needing to create a router object.

Use of Dynamic Routing:

• Scalability: The routes can be easily managed and scaled as the application grows.
• Reduce redundancy and centralize route definitions to improve maintainability.
• Flexibility: Routing logic can be adjusted based on dynamic conditions, such as user roles, request parameters, or external data.

Syntax:

It has the following syntax:

Where METHOD is the request's HTTP method, path is the route's path, and callback is the function that will process the request.

Steps to dynamically call router function in Node.js

Step 1: Install the npm install express

Step 2: Check Express Version

After installing the express module, enter the command to check the express version in the command prompt.

Step 3: Create the server

Step 4:

Example 1:

Output:

 node index.js Server running on http://localhost:3000 http://localhost:3000/user 

Explanation:

The example code shows how to dynamically load and register route handlers in an Express.js application, which improves scalability and maintainability. Initialization is performed by the index.js file, which includes Express server setup and definition of the loadRoutes function. This loadRoutes function is expected to dynamically include all route modules from the routes directory, necessitating the use of fs in Node.js to read this directory for each module. An object must be produced by each imported route module, which contains a path and an instance of an express router that should be registered via app.use with the main Express application.

The creation of new files in routes allows new routes to be added effortlessly, each with its own logic and path. When the server starts up, it reads these files automatically to register the routes. This feature ensures easy management and expansion of the application's routing structure: requests made through specified URLs (like /user or /product) on a web browser should confirm proper registration and handling by displaying corresponding messages ("User Home" or "Product Home").

Example 2:

Output:

 node index.js Server listening on PORT 3000 This is the gadgets category This is the furniture category http://localhost:3000/furniture/456 This is the apparel category This is the product page for gadget item 123 

Conclusion:

In conclusion, dynamic routing in Node.js with Express is an effective technique for managing large applications. By programmatically loading routes, we can improve our application's scalability, maintainability, and flexibility. This method is especially useful in large-scale applications where the number of routes can become overwhelming if manually managed.