node-express-chat

Node.js and Socket.io make full-duplex communication easy (full 2-way, like a cell phone conversation)

Links

• Source

Requirements

• Node.js (and npm, included with Node)
• A browser (e.g., Chrome)
• A text editor with a terminal (e.g., VS Code)

Responsive Style

• Tachyons

Benefits

• Still no build tools needed
• Node.js non-blocking event loop supports many concurrent requests
• Socket.io makes full duplex communication easy
• Express provides middleware, static-file serving, and routing.
• Multiple browser clients can exchange messages immediately.

Earlier Examples

• node-server
• node-express-app

Terminal 1. Install Dependencies

Open default terminal (if Windows use PowerShell) in the root project folder and run:

npm update
npm install
npm audit fix

Terminal 1. Run the App

In the same terminal, start your app.

npm run dev

Keep this terminal open while using the application. Nodemon starts the server and restarts it when application files change. A successful startup should report something similar to:

[nodemon] starting `node app.js`
Server listening on 0.0.0.0:3003
Open http://localhost:3003/

The address 0.0.0.0 means that the server is listening on all available IPv4 network interfaces. Do not enter http://0.0.0.0:3003/ in the browser - it's is a server binding address rather than a browser destination.

Optional: Click to Verify Server

Terminal 2. Verify the Server

Leave Terminal 1 open with the server running. Open a second terminal in the root project folder. Verify that the server is accepting connections on port 3003.

If Windows PowerShell, use:

Test-NetConnection localhost -Port 3003

If macOS or Linux use:

nc -zv 127.0.0.1 3003

Success might appear like this:

WARNING: TCP connect to (::1 : 3003) failed

ComputerName     : localhost
RemoteAddress    : 127.0.0.1
RemotePort       : 3003
InterfaceAlias   : Loopback Pseudo-Interface 1
SourceAddress    : 127.0.0.1
TcpTestSucceeded : True

Or request the page directly from the server:

curl.exe -i http://localhost:3003/

A successful request should start with:

HTTP/1.1 200 OK

Use the results to help identify problems:

• TcpTestSucceeded : False means the server is not accepting connections on port 3003.
• HTTP/1.1 404 Not Found means Express could not find the requested page.
• HTTP/1.1 500 Internal Server Error means the application encountered an error.
• HTTP/1.1 200 OK means Express successfully returned the page.

Open a Browser Client

1. Open a web browser.
2. Go to the URL: http://127.0.0.1:3003/ or http://localhost:3003/.

Find Your IP Address

Open PowerShell as Admin, run ipconfig. Locate your IPv4 address. Invite others to interact with your hosted chat app.

Terms

• full duplex
• hoisting
• npm install
• npx fixpack
• Socket.io

Reference

• Create Simple Chat App Using Node.js, Express, and Socket.io

See Also

• More App Examples
• fixpack - auto-organize package.json