Riot vs Ractive.js

Riot takes the expressions from a DOM tree and stores them in an array. Each of these expressions points to a DOM node. On each cycle these expressions are compared to the values in the DOM. So when a value has changed, Riot automatically updates the corresponding node. This way the operations are kept to a minimal amount and since the expressions can be cached, going through 1000 of them takes less than 1ms.

Riot is made to be used with websites of any kind, so it's built to be easy and lightweight, but still maintaining all the needed features for a UI library. It's only 2.5 KB in size when minified. So it can also be used for mobile web apps without requiring much bandwidth to download.

Riot components use custom tags which are nothing more than familiar HTML tags coupled with JavaScript. This eliminates the need to learn another templating language or syntax. For example:

<todo>
    <h3>TODO</h3>

    <ul>
        <li each={ item, i in items }>{ item }</li>
    </ul>
    <form onsubmit={ handleSubmit }>
        <input>
        <button>Add #{ items.length + 1 }</button>
    </form>

    this.items = []

    handleSubmit(e) {
        var input = e.target[0]
        this.items.push(input.value)
        input.value = ''
    }
</todo>

Riot tries to separate HTML and JavaScript, while still keeping them inside the component. This way, the HTML can also be neatly mixed with JavaScript expressions.

Riot has support for server side rendering. The views and data are rendered on the server, then those views are sent as HTML to the browser when a user requests them.

This helps with initial loading time and is very useful for SEO purposes because the web app is indexed by search engines same as other static websites that have their HTML on the server.

It is very easy to use your favorite preprocessors with the Riot compiler. Riot comes with CoffeeScript, ES6 (Babel), TypeScript, LiveScript and Jade support. You can also add your own parsers.

It makes React look confusing as hell. Nothing against React - It's just that easy to implement!

Riot supports scoped CSS inside components for every browser by rewriting stylesheet rules.

Since it's not opinionated, even the scripting can be in anything that can be transpired to JavaScript.

RiotControl is inspired by Facebook's Flux Architecture Pattern and it's a simple Central Event Controller/Dispatcher for Riot. It's extremely lightweight (like Riot itself) but unfortunately passes up on some features in favor of performance and simplicity.

RiotControl helps with storing the stater of the application, by passing events from views to stores and vice-versa. Stores can communicate with many views and views can do the same with many stores, this enables to clearly separate concerns and inter-component communication.

Ractive fully supports a templating language. To be more precise, views are written with a variant of Mustache, which is also extended to support inline JavaScript expressions. Soon it will be able to support other templating languages.

Ractive has a concept of proxy events, which translate a user action (e.g. a mouseclick) defined via an event directive into an intention (e.g. 'select this option'). This allows you to handle user interaction in a readable, declarative fashion.
on-click='activate'
with arguments:
on-click = 'activate: {{a}}, {{b}}'
It's activate (and not click, nor your function name) that is the name of the handler event that will be fired for any registered handlers created via
ractive.on('activate', your_handler)
ractive.on('activate', your_another_handler)

Of course, Ractive also supports method calls like on-click='toggle(foo)'

Two-way binding can be turned off by those that are concerned it may be a source of bugs.

They have a great interactive tutorial which makes the learning process easy peasy. You will get into it within a couple of minutes.

Instead of relying on the DOM, Ractive implements a virtual DOM from scratch, allowing it to calculate precisely what needs to be patched during the next screen refresh. This is orders of magnitude faster than fiddling with the DOM itself.