How does NodeJS works?

What is NodeJS

and why it is so different

JavaScript runtime built on Chrome's V8 JavaScript engine. Node.js uses an event-driven, non-blocking I/O model that makes it lightweight and efficient.

Background

  • Released in 2009
  • Nearly a commit a day
  • Created by Ryan Dahl, for interactive web app with maximum throughput and efficiency
  • Sponsored by Joyent, specialized in high-performance cloud computing
  • Used by LinkedIn, eBay & PayPal

The Architecture

NodeJS is ..

  • Very Fast in code execution
  • Asynchronous & Event-driven
  • Single-threaded, Non-blocking I/O calls
  • High scalability

Single-threaded?

Isn't multi-threaded faster?

Not exactly!

Single vs Multi threaded

Clients

Threads

I/O operations

Assuming that each thread potentially has an accompanying 2 MB of memory with it, running on a system with 8 GB of RAM puts us at a theoretical maximum of 4000 concurrent connections, plus the cost of context-switching between threads.

By avoiding all that, Node.js achieves scalability levels of over 1M concurrent connections.

Node Async

Call Stack & Event Loop

The Stack

Sync in browser is bad..

The solution?

Asynchronous Callbacks

The Event Loop

When to use NodeJS

..and when not to?

NodeJS is perfect for

  • I/O bound Applications
  • Data Streaming Applications
  • Data Intensive Real time Applications (DIRT)
  • JSON APIs based Applications
  • Single Page Applications

NodeJS is not for

CPU intensive applications

How does NodeJS works?

By Wan Mohd Hafiz

How does NodeJS works?

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