Express: Start and write to console

README.md

ExpressJS: Start, Listen and Console.log()

Prerequisites

1. Initialized npm project with package.json file. See: Getting started with npm.
2. express installed as project dependency.
3. Entry page (i.e. server.js) present in the project root.

Example directory structure

project-root
    ├── node_modules
    ├── package-lock.json
    ├── package.json
    └── server.js

Instructions

1. In your favourite editor (VSCode), open the file server.js

2. Add JS code to load express as a program dependency:

   const express = require('express');

3. Create an instance of the Express server. Express wants you to start by invoking the function that express exports to require().

   const app = express();

   • express() returns a JS object. It includes many functions that come in handy. Let's use those functions now.

4. Set a variable for the port that the server will listed to. For now, let's go with port 4000:

   const PORT = 4000;

5. Instruct the server to listen to the PORT:

   app.listen(PORT, function(){
     console.log(`Listening on port ${PORT}`);
   });

• Our node program (an Express server!) will start in the terminal window (making it pretty useless, besides logging to the console).

package.json

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

server.js

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

const PORT = process.env.PORT || 4000;

//
// Start up and wait for incoming requests
//
app.listen(PORT, function() {
  console.log(`Listening on port ${PORT}`);
})