Node Examples

This is a collection of examples for node.js and express.js. Includes a short intro to JavaScript patterns in node.js.

The most up-to-date examples are:

• ExpressIntro - this section contains a many examples using express.js, including:
  • FourLineServer - a minimal static file server
  • staticPages - shows how to serve static pages as well as dynamic routes
  • getPost - shows how to handle GET and POST requests, and how to handle json request data and form-urlencoded data
  • getPostPutDelete - shows how to use express.js .all() function to listen for any type of request (GET, POST, PUT, DELETE)
  • requestHeaders - shows how to get the raw headers of an HTTP request
  • restParameters - shows how to read RESTful parameters from the route of a request. subroutes
  • fileUploader - shows how to use multer.js to make a web page that can upload files to your server. routes
  • subroutes - shows how to handle different RESTful subroutes
• glitch-examples - these are examples for express.js, mqtt.js, websockets using ws.js, and node-fetch.js that I’ve posted on glitch.com. Some of these duplicate the express intro examples above.
• HTTPS server - shows how to use express to respond to HTTPS requests.
• SerialIntro - a few examples showing how to use Serialport.js
• NodeWithNginx - a minimal proxy server to combine with nginx.

There are other examples in the main directory as well.

Creating a node.js Project

Node.js runs in a command line interface. You can edit your files in any editor you want. A typical node.js project has the following structure:

• ProjectDirectory/
  • main_script.js - your main JavaScript program
  • package.json - a manifest of dependencies
  • package-lock.json - describes any changes that need to be made to package.json
  • public/ - a directory for static files
    • index.html - static files to be served
    • style.css
    • script.js

To make a new project, create a directory for it, then create a main script file, which is usually a server, then use npm to install any libraries you know you’ll use and initialize a package decription called package.json. For example, if you were making a project using express.js to make a web server, you’d start the project like so:

$ mkdir project-dir 
$ cd project-dir
$ touch server.js
$ npm install express
$ npm init

npm will ask you a series of questions to fill out the package description, then it will generate two files, package.json and package-lock.json, and a directory, node_modules. The first, package.json, is your project description, and the second,package-lock.json, describes any changes that need to be made to package.json or node_modules. The directory node_modules is where npm downloads the libraries that you install, and any other dependencies. The two files, package.json and package-lock.json, should be included in any repository in which you store your files, so that the project can be recreated.

Installing an Existing Project

To re-create a project downloaded from a remote repository change directories into the project and use npm to install the dependencies. If package.json and package-lock.json exist, the command npm install will read them and install all needed dependencies into node_modules.

Running a Project

Once you’ve got everything installed, you can run a project from the command line with the main script’s name like so:

$ node server.js

Type control-C to stop the project. If you need to run it in the background for as long as the host is running, consider using PM2.

Running on Glitch.com

If you’d like to run these on glitch.com or heroku or another node.js host, you may need to change the port number to comply with whatever port the platform runs your scripts on. On glitch.com, you can use:

process.env.PORT || portnumber

in place of the port number given in these scripts. Some of them have been adjusted accordingly.