Introduction to Node.js
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Node.js is a JavaScript runtime built on Chrome's V8 engine that allows JavaScript to be run on the server side. It is single-threaded, non-blocking, and asynchronous which means it relies on callbacks and an event loop to handle concurrent operations like I/O instead of blocking threads. The event loop handles callbacks by placing them in a queue to be executed once the current thread is complete. This allows Node.js to handle a large number of concurrent connections efficiently. Some common uses of Node.js include real-time applications, proxies, and chat applications due to its asynchronous nature. It is not well-suited for heavy computation or large web applications.
Introduction to Node.js
- 1. Introduction to Node.js Single threaded, non-blocking, asynchronous runtime (server side Javascript)
- 2. About me? NodeXperts? Premier Software Development Services Company. Build & Deliver for Node.js. Tremendous work in : Angular.js, D3.js, Meteor.js, ReactJs and many more.
- 3. intro to Javascript. What the heck is an event loop?
- 4. What is javascript? JavaScript has “event-loop”, “callback” and a stack. It is “asynchronous”, “single-threaded” and “non-blocking”. It uses v8 engine for runtime. What does it mean? Everything revolves around “event loop”.
- 5. V8 Engine?
- 6. Stack Call? function foo2() { console.log(“hello world”); } function foo1() { foo2(); } foo1(); Stack: Finally: hello world foo2() foo1() main()
- 7. What happen when we run code synchronously in single threaded environment? var request1 = $.getSync(‘http://xyz.com’); var request2 = $.getSync(‘http://xyz1.com’); console.log(request1); console.log(request2) What will happen? 1.request1 will process, then wait for the response. 2.Request2 will process, again wait for response. Why? Coz thread is busy processing that request.
- 8. Then, how Javascript works asynchronously? The answer lies in event loop? What this event loop is? Let’s see...
- 9. What is Node.js then?A server side v8 engine I hope you now have a basic idea of how javascript works on browser?
- 10. What? Now we can run javascript on server side. Yes, it allows us to run JavaScript code in the backend, outside a browser. How? Google's V8 VM. Comes with two things: a runtime environment and a library (NPM). Sounds awesome, right?
- 11. Features of Node Js Relies on asynchronous code to stay fast and non-blocking. Non-blocking Blocking: console.log("Hi!"); for(var i=0; i<100; i++) { console.log("Inside the loop"); } console.log("Welcome to NodeXperts.");
- 12. Continue... Non-blocking: console.log("Hi!"); setTimeout(function timeout() { for(var i=0; i<100; i++) { console.log("Inside the loop"); } }, 5000); console.log("Welcome to NodeXperts."); Where does it go? It goes inside EVENT LOOP (through callbacks).
- 13. Let’s take a look at an example var fs = require('fs'); fs.readFile('nx.txt', function (err, data){ if(err) throw err; console.log(data); })
- 14. While there are events to process: e = get the next event Perform the action requested by e in thread If e’s thread is complete and there is a callback associated with e: Call the callback
- 15. Continue... Event Loop: How it is different from browser?
- 16. Where you can use Node Js? Few CPU cycles I/O operations Chat Applications Proxies
- 17. Where you can not use Node Js? Heavy computation. Large and complicated web application because it doesn’t support multi-threaded programming.
- 18. Advantages of Node Js Open source JavaScript language is used on both front-end & back-end High Scalability both Horizontally & Vertically Better Performance than traditional web servers Has a wide community of developers around the world
- 19. Thank you Any questions? Hope you all enjoyed :)