Explain Event driven applications , how is it different from callback

1.	Explain Event driven applications , how is it different from callback function, module used and classes used with examples?
Answer» Node.js uses Events heavily. Most of Node.js API’s are BUILT on Event driven architecture. Every action on a computer is an event. Example: File OPENING is an event. Objects in Node.js can fire events like createReadStream object FIRES when opening or closing a file. Example: to read a stream of characters in existing file trnk.txt var fs = require("fs"); var rdstream = fs.createReadStream('trnk.txt'); rdstream.on('open', function(){ console.log("File OPENED"); }); Executing above code you will get result as *File Opened* You can create, fire and listen to your events using Events module, eventEmitter class. Events module and eventEmitter class is used to bind events and event-listener.

Explain Event driven applications , how is it different from callback function, module used and classes used with examples?

Answer»

Node.js uses Events heavily. Most of Node.js API’s are BUILT on Event driven architecture.

Every action on a computer is an event.

Example: File OPENING is an event.

Objects in Node.js can fire events like createReadStream object FIRES when opening or closing a file.

Example: to read a stream of characters in existing file trnk.txt

var fs = require("fs"); var rdstream = fs.createReadStream('trnk.txt'); rdstream.on('open', function(){ console.log("File OPENED"); });

Executing above code you will get result as

File Opened

You can create, fire and listen to your events using Events module, eventEmitter class.

Events module and eventEmitter class is used to bind events and event-listener.