Building web application with Express.js
Express.js([https://expressjs.com](https://expressjs.com)), or Express, has been and remains the most popular web framework for building web application in Node.js. In this post, we will look at how to create an Expressjs web server. ## <br>Getting ready --- To get started, we'll create a folder named **express-app** and initialize our project by running the following commands: $ mkdir express-app $ cd express-app $ npm init --yes ## <br>How to do it --- In this recipe, we'll create a web server that responds on the / route using. 1. First, let's start by installing the `express` module: $ **npm install express** 2. Now, we need to create a few directories and files for our web application. While in your `express-app` directory, enter the following commands int your Terminal: $ touch app.js $ mkdir routes public $ touch routes/index.js public/style.css 3. Our app.jss file is where we instantiate `express`. Open the `app.js` file and import the following dependencies: ```js const express = require("express"); const path = require("path"); const index = require("./routes/index"); ``` 4. Next we'll define the port for our express.js server: ```js const PORT = process.env.PORT || 3000; ``` 5. Now we can initialize `express`: ```js const app = express();; ``` 6. Next we'll register the `static` Express.js middleware to host the public directory. We will also mount our `index` route: ```js app.use(express.static(path.join(__dirname, "public"))); app.use("/", index); ``` 7. Finally, in `app.js`, we need to start our Express server on our specified port: ```js app.listen(PORT, () =>{ console.log(`Server listening on port ${PORT}`); }); ``` 8. We now need to add our route handling in the `index.js` file that is within the `routes` directory. Add the folllowing to `index.js`: ```js const express = require("express"); const router = express.Router(); router.get("/", (req, res) => { const title = "Express"; res.send(` <html> <head> <title>${title}</title> <link rel="stylesheet" href="style.css"> </head> <body> <h1>${title}</h1> <p>welcome to ${title}</p> </body></html> `); }); modul.exports = router; ``` 9. Now we can add some styling to our application using CSS. Add the following to `public/styles.css` ```css body { padding: 50px; font: 14px "Lucida Grande", Helvetica Arial, sans-serif; } ``` 10. Now we can start out Express.js server by running the following command: ```bash node app.js ``` Navigate to [https://localhost:3000](https://localhost:3000) and you will see the result in your browser. If you like content like this, take part in the site by commenting or liking it. Thank you