How to Get Started with Express?

Introduction

Express is a free and open-source back end web application framework for Node.js, which allows the creation of web applications and APIs in a much easier and cleaner way.

In this tutorial, we will see how to create a package.json file and install Express.

Prerequisites

I am assuming you already have Node.js and npm installed on your system. To install Node.js and npm follow How to install Node.js on Ubuntu 20.04 or How To Install latest version of Node.js on Ubuntu 20.04

Create package.json file

Let’s start with creating a directory for our application.

                    
                        mkdir express-app
                    cd express-app
                    
                

Now create package.json for our application, to do this we will use the command npm init.

                    
                        npm init
                    
                

This command will prompt us with many things like the package name, version etc. You can simply press Enter to accept the default for most of them.

                    
                        package name : (express-app)
                    
                

If you plan to publish your package, the most important thing in your package.json is the name. If you want to change the package name then provide here then press enter or simply press Enter to accept the default.

                    
                        version: (1.0.0)
                    
                

version is the second most important thing in your package.json file after the name. to accept the default version number press Enter.

                    
                        description:
                    
                

You can put a description in it. Press Enter to leave it empty.

                    
                        entry point: (index.js)
                    
                

Here you can provide the name for the main file. For this tutorial, I want to call it app.js

                    
                        entry point: (index.js) app.js
                    
                

If you want it to be index.js just press Enter.

                    
                        test command:
                    
                

Here you can provide the command which runs whenever you call npm test, for now just press Enter to skip, we will discuss it in another tutorial.

                    
                        git repository:
                    
                

If you have set up a git repository for the application then you can provide the link here otherwise press Enter to skip.

                    
                        keywords:
                    
                

Here you can provide keywords that are relevant to the package that you would expect people to use while searching for a package like yours. To skip press Enter.

                    
                        author:
                    
                

If you want to provide author information give it here or press Enter to skip.

                    
                        license: (ISC)
                    
                

Any license information can be put here, press Enter to skip.

                    
                        About to write to .../express-app/package.json:
                        {
                        "name": "express-app",
                        "version": "1.0.0",
                        "description": "",
                        "main": "app.js",
                        "scripts": {
                            "test": "echo \"Error: no test specified\" && exit 1"
                        },
                        "author": "",
                        "license": "ISC"
                        }

                        Is this OK? (yes)
                    
                

Type ‘Y’ to confirm and press enter.

Install Express

Now our package.json file is ready. Let’s install Express in the express-app directory and save it in the dependencies list.

                    
                        npm install express --save
                    
                

Now Express has been installed and a new directory node_modules has been created in our application directory and our package.json file also got updated.

                    
                        {
                        "name": "express-app",
                        "version": "1.0.0",
                        "description": "",
                        "main": "app.js",
                        "scripts": {
                            "test": "echo \"Error: no test specified\" && exit 1"
                        },
                        "author": "",
                        "license": "ISC",
                        "dependencies": {
                            "express": "^4.17.1"
                        }
                        }
                    
                

Conclusion

In this tutorial, You have created a package.json file using npm init and successfully installed Express version 4.17.1. You can continue learning by following “Hello World!” Program With Node.js and Express.