This document provides an introduction to Node.js, including who uses it, why it is used, when it is appropriate to use Node.js, and how to get started with Node.js. Some key points are that Node.js is event-driven and non-blocking, which makes it suitable for real-time applications with lots of concurrent connections. It also discusses when not to use Node.js, such as for computationally heavy applications, and how to install Node.js, create a basic HTTP server, and use the NPM package manager.

1. Node.js basics
“a purely evented, non-blocking infrastructure to script highly concurrent programs”
Gergely Nemeth

2. Users
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● eBay
● LinkedIn
● Yahoo
● Heroku
● Medium
● Yammer
● Trello
● etc...

3. Why?
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● Uses V8
● Non-blocking
● Event-driven
● CommonJS module format

4. When to use it?
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● Lots of non-blocking operations
● JSON APIs
● Reuse code across the client and the server
● Shelling out to unix tools
● Streaming data
● Crawling

5. When to forget it?
LongDatabaseOperation.on(‘finish’, function () {
//won’t be called!
});
while (true) {
//do some stuff
}
Gergely Nemeth
● Computationally heavy applications

6. When to forget it?
LongDatabaseOperation.on(‘finish’, function () {
//won’t be called!
});
while (true) {
//do some stuff
}
Gergely Nemeth
● Computationally heavy applications
1. All code runs in a single thread
2. Functions listen on events, act and sleep

7. How?
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● Download from: http://nodejs.org/ (or nvm on unix-based systems)
● Hello world:
// Load the http module to create an http server.
var http = require('http');
// Configure our HTTP server to respond with Hello World to all requests.
var server = http.createServer(function (request, response) {
response.writeHead(200, {"Content-Type": "text/plain"});
response.end("Hello Worldn");
});
// Listen on port 8000, IP defaults to 127.0.0.1
server.listen(8000);
// Put a friendly message on the terminal
console.log("Server running at http://127.0.0.1:8000/");
● Run with: node app.js

8. NPM
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● Node Packaged Modules
● package.json
{
"name": "MyAwesomeApplication",
"version": "0.0.0",
"dependencies": {
"nodemailer": "~0.5.2",
"express": "~3.3.4"
}
}
● npm install
● npm install XX --save

9. Next...
Gergely Nemeth
● Node.js best practices
● Express, Passport
● Websockets with Socket.io
● MongoDB with Mongoose
● Redis
● Hogan.js (mustache)