A brief overview of Knockout.js
Posted October 10, 2013on:
Almost everyone involved in web development knows jQuery or at least heard of it. Being simple and concise, it makes web developers’ life much simpler. But could it be a solution to every problem? Unfortunately not. Once you decided to create more complex web apps, you are to face a problem, as there is no easy way to make your UI and data communicate with each other dynamically. And you need a library which will provide you with a more sophisticated way of communication between your UI and the underlying data model. And here is where Knockout (KO) could help.
What is Knockout?
– Dependency Tracking
The right parts of your UI are automatically updated whenever your data model changes. This is achieved by the two way bindings and a special type of variables called observables. You don’t have to worry about adding event handlers and listeners for dependency tracking.
– Declarative Bindings
This becomes useful when your application becomes more complex and you need a way to display a rich structure of view model data, thus keeping your code simple. Knockout can use alternative template engines for its template binding. It has a native, built-in template engine which can be used right away.
– Compatibility and Extensibility
Knockout is compatible with any back-end technology and on the front-end it does as much or as little as you decide. It leaves many decisions to you to make, thus letting pick the best tool to meet your specific needs. Knockout doesn’t care about how you communicate with the server or how you choose to do routing, but there are several third party libraries that do a fine job of these things (like sammy.js for routing and upshot.js for data-access). It goes without mentioning that it works fine next to jQuery. Knockout is also easily extensible. To modify or extend the default functionality, it offers features like custom bindings, and custom functions. There are also several plugins already written for KO.
– Ease of Learning and Use
Some additional benefits are the following:
• It can be added on top of your existing web application without requiring major architectural changes
• It’s compact – around 13kb after gzipping
• It works on any mainstream browser (IE 6+, Firefox 2+, Chrome, Safari, others)
• Comprehensive suite of specifications (developed BDD-style) means its correct functioning can easily be verified on new browsers and platforms
– HTML views can get messy as declarative bindings increase. This can be weakened to some extent through the use of custom bindings, computed observables and by attaching events to the DOM using jQuery instead of using the data-bind attribute.
– Additional functionality like data-access and url-routing are not included. If you are looking for an end to end solution that offers a complete toolbox of common web-app functionality, you should probably check out such frameworks as Angular or Ember.
Knockout VS jQuery
Knockout.js is not a replacement of jQuery (as well as of Prototype, or MooTools). It doesn’t attempt to provide animation, generic event handling, or AJAX functionality (however, Knockout.js can parse the data received from an AJAX call). Knockout.js is focused only on designing scalable and data-driven UI.
Moreover Knockout.js is compatible with any other client-side and server-side technology. It also acts as a supplement to the other web technologies like jQuery and MooTools.
Although you will need to use Knockout with jQuery at the same time, in some cases like animated transitions, Knockout itself doesn’t depend on it. Another thing you need to understand is that Knockout doesn’t compete with jQuery – they both do excellent job; each one in its own direction. And if you want to get the most benefits you should use them together.
Knockout is the simplest of all the frameworks as well as one of the smallest. It does not claim to be able to solve all your problems, but it does claim to do a few useful things and do it better than the alternatives. In the words of Knockout creator Steve Sanderson, it is “low risk” because its uses are focused and it is compatible with any other technologies you are using and you can use it in a very small part of your application or your entire application. For someone who wants to take their project to the next level without too much risk, knockout is a great choice.
Hope you found the information in this article useful. Your valuable feedback, question, or comments about this article are always welcome!🙂