Controller in ExpressJS

ExpressJS is a popular web application framework for building web applications in Node.js. In this tutorial, we will discuss the concept of controllers in ExpressJS and how they can be used to organize and manage the application logic.

Controllers in ExpressJS are responsible for handling requests and generating responses. They help in separating the concerns of the application by organizing the logic into different modules. This makes the code more manageable and maintainable.

Here are some key points about controllers in ExpressJS:

• Controllers are JavaScript functions that are responsible for handling specific routes or endpoints.
• They are typically placed in a separate file and imported into the main application file (app.js).
• Controllers can access the request and response objects, and they are responsible for generating the response to the client.

Creating a controller in ExpressJS is quite simple. Here is an example of a basic controller that handles a GET request:

“`javascript
// myController.js

const myController = (req, res) => {
// Application logic goes here
res.send(‘This is the response from my controller’);
}

module.exports = myController;
“`

Once the controller is created, it can be imported into the main application file and used to handle specific routes. Here is an example of how to use the above controller in ExpressJS:

“`javascript
// app.js

const express = require(‘express’);
const myController = require(‘./myController’);
const app = express();

app.get(‘/my-route’, myController);

app.listen(3000, () => {
console.log(‘Server is running on port 3000’);
});
“`

With the above setup, whenever a GET request is made to the /my-route endpoint, the myController function will be called and it will send the response ‘This is the response from my controller’ to the client.

Controllers in ExpressJS are a powerful tool for organizing the application logic and handling requests. They help in keeping the code clean and maintainable, and they are a key concept to understand when working with ExpressJS.

For more tutorials on ExpressJS and other web development topics, be sure to check out Abhinay Jangde’s YouTube channel and website. Happy coding!