What is Knockout.js and how is it different from jQuery?

07 Sep 2022

Knockout.js is a javascript library that allows us to bind html elements against any data model. It provides a simple two-way data binding mechanism between your data model and UI means any changes to data model are automatically reflected in the DOM(UI) and any changes to the DOM are automatically reflected to the data model.

Why Knockout

consider a simple example of shopping-cart interface for an e-commerce website. When the user deletes an item from the shopping cart, you have to remove the item from the underlying data model and remove the associated html element from the shopping cart and also update the total price. If you are not using knockout for doing this you have to write event handlers and listeners for dependency tracking.

The Knockout.js provides a simple and convenient way to manage this kind of complex, data-driven interfaces. Instead of manually tracking, each element of the HTML page rely on the affected data and will automatically updated the DOM when any changes to the data model occurs.

Knockout Features

  1. Declarative Bindings

    This allows you to bind the elements of UI to the data model in a simple and convenient way. When you use JavaScript to manipulates DOM, this may cause broken code if you later change the DOM hierarchy or element IDs. But with declarative bindings even if you change the DOM then all bound elements stay connected. You can bind data to a DOM by simply including a data-bind attribute to any DOM element.

  2. Dependency Tracking

    This automatically updates the right parts of your UI whenever your data model changes. This is achieved by the two way bindings and special type of variables called observables. You don't worry about adding event handlers and listeners for dependency tracking.

  3. Templating

    This comes in handy 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. Knockout has a native, built-in template engine which you can use right away and can be customize how the data and template are executed to determine the resulting markup.

  4. Extensible

    This implements custom behaviors as new declarative bindings for easy reuse in just a few lines of code. Knockout is also flexible to integrate with other libraries and technologies.

Knockout VS jQuery

Knockout.js is not a replacement of jQuery, 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. Knockout.js acts as a supplement to the other web technologies like jQuery, MooTools.

MVVM Design Pattern

Knockout.js uses a Model-View-ViewModel (MVVM) design pattern in which the model is your stored data, and the view is the visual representation of that data (UI) and ViewModel acts as the intermediary between the model and the view.

Actually, the ViewModel is a JavaScript representation of the model data, along with associated functions for manipulating the data. Knockout.js creates a direct connection between the ViewModel and the view, which helps to detect changes to the underlying model and automatically update the right element of the UI.

What do you think?

I hope you will enjoy the article and understand what is knockout. I would like to have feedback from my blog readers. Your valuable feedback, question, or comments about this article are always welcome.

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