When comparing Knockout vs Deku, the Slant community recommends Knockout for most people. In the question“What are the best React.js alternatives?” Knockout is ranked 6th while Deku is ranked 18th. The most important reason people chose Knockout is:
Ranked in these QuestionsQuestion Ranking
Pro Easy data binding
Pro Easy to learn
Has a low entry barrier and an easy learning curve. It's especially easy to learn for beginners.
Pro Legacy browser support
Supports a large number of browsers, including IE6.
Pro Built in templating
Bindings in Knockout can also be used to control the generated structure of the HTML. There are bindings provided to allow for iteration and conditionals. The structure of the html reflects the structure of the data so iterative elements are bound to arrays in the data model. Having the HTML structure maintained by bindings keeps the templating simple, easy to read, and maintain.
Knockout also allows for string based templating so you can use whatever templating library you prefer.
Pro Great documentation
The excellent tutorials with built-in exercises are a great learning experience, even for people without prior MVVM and data binding experience.
Pro Dynamic models help with keeping the code simple and clean
Models in Knockout can be watched to keep the page data up to date by using observable objects. The observables notify Knockout when data is changed and automatically updates the page when this happens. By having Knockout maintain this relation, it keeps the front end code cleaner and simpler, and by enforcing a consistent pattern with observables the methodology can be more robust.
Pro Lightweight and plays nicely with other libraries
Pro It's only a library
Knockout does one thing, and does it well. It doesn't try to take on more than one area. It does MVVM data binding and that is it.
Pro Very flexible
One can do a lot of things and it keeps self references and other types of loops under control.
Pro Simple manageable modules
Using components is a great way of breaking up large modules into simpler ones.
Pro Server side rendering
Deku can render it's components and data server side, then it sends those components as HTML to the browser.
This ensures faster initial loading time and SEO friendliness out of the box, since it's indexed as any other static website by search engines.
Pro Easy to learn
Since Deku is very lightweight and has a rather small API, there's not much to learn. It's pretty easy to get started and build something with it.
Pro Can use JSX
Developers using Deku can choose to also use JSX if they want to. This is especially helpful for people who are moving from React to Deku.
Pro Good performance
Deku's diffing algorithm is considerably faster and performs better than most libraries. The dbmonster performance mini-app written in Deku renders roughly 16% faster than other libraries.
Con Seems to be dead
KO has been stuck at version 3.4 for a long time, and there's not a lot of community activity.
Con Can become complex once the application grows large
Knockout leaves the application structure to the developer and it can become quite complex and unmanageable in the hands of a beginner once the application grows large and complex.
Con Two way binding requires a little extra work
When allowing users to edit existing data, the two-way binding of observables means you'll need to have to save original values before they're edited, to make comparisons or revert if the user cancels the action.
Con Slower than others when amount of objects grows
Knockout has a bad performance when the dealing with large amount of objects. You can see more here.
Con No support for legacy browsers
Deku does not support legacy browsers, or relatively old browsers for that matter. They only support the latest versions of the major web browsers.
Con Not a lot of learning resources
Since it's a rather new library and has a small community, there are not many examples where you can learn from out there. There are also few guides and the documentation is not amazing and has some parts that should be covered better.