Node.js commands- Create your First App

The Node.js commands discussed in this post are important for any beginner to create web applications in Node.js.

uninstall

This is the opposite command of install command that was discussed in the previous post on node.js. With install command we could install a package and a folder is created under “node_module” folder in your application folder. The uninstall command is used to uninstall any module that is no longer required in a particular project. This command removes the package mentioned along with the folder created under “node_module” folder.

Syntax

npm uninstall package_name

The example discussed below uninstalls the express package from the current project. You will notice that the express folder created in node_module” folder is removed after the following command.

npm uninstall express

update

The next important command is update command. It is used to update the previously installed package in the web application folder. This is essential if the package that you are using in your application is revised by the third party vendor who provided it to the developer community. This command is used to update a package to the latest version of that module. If the package is already the latest version, no change will be displayed.

Syntax

npm update package_name

In the example below, the express package will be updated with its latest version.

npm update express

ls

This command lists down all the modules/packages installed in the npm. This way you will know that which packages are available to be used and which you still have to update.

Syntax

npm ls

search

search command is typed in the shell to search through package metadata for all files available in the registry of packages.

Syntax

npm search package_name

Example

npm search express

init

init command is used to initialize a node.js app

Syntax

npm init

Creating first app in node.js

Now that you are aware of Node.js commands try this example to understand how to create your first node.js application. Copy the below code in a javascript file (here named app.js) and save it in the directory. This folder also contains the packages to be used further on in later stages of project development.

The process.exit(1) is be used in JavaScipt to exit from the node.js program.

var express = require('express');
var app = express();

app.get('/', function (req, res) {
   res.send('Welcome to your first Node.js App');
})

var server = app.listen(8081, function () {
   var host = server.address().address
   var port = server.address().port
   
   console.log("Example app listening at http://%s:%s", host, port)
})

This JavaScript file is executed by using the command in the command line or shell.