xow

A xain-based view engine for the browser

Note: the usage of xow in the browser is critically dependent on the following ES2015 features:

• Proxies
• Symbols
• const / let
• Everything else required by xain

tl;dr - use only on latest chrome versions!

Example code

You can tour a JSX example usage of xow right here.

The cogs of the machine

const { Component, renderTo, dom, ComplexComponent } = require('xow');

Okay, let's start of by splitting these cogs into 2 groups:

Core

Component

Possibly the most important function here. xow revolves around using components sharing a single observable (as in xain observable) state. Component is a function (not a class! not a class!) that accepts a single observable state, and returns the base class your actual components should inherit from. So, first step to creating a new app would be creating the following module:

// components/base.js
 
const {Component} = require('xow');
const {observable} = require('xain');
 
const state = observable({
    firstName: 'Foo',
    lastName: 'Bar',
    age: 23
});
 
const App = Component(state);
 
module.exports = App;

Awesome! You have a base App class now 😄 Now, lets write our first component up:

// components/main.js
 
const {dom} = require('xow');
const App = require('./base');
 
/*
The Main constructor accepts `props` (a plain object) that constains the key `children` (an array).
It can be neglected for a default value of `{}`.
*/
module.exports = class Main extends App {
    /*
    This is the *view spec* of the component.
    A xain view of the App's state is created with this static spec, to create an observable reduction
    of the main state, specifying to which state changes this component should react to.
    This view's properties are combined into the `this.props` property.
    */
    static view() {
        return {
            age: 'age',
            name({firstName, lastName}) {
                return `${firstName} ${lastName}`;
            }
        }
    }
    /*
    You know this one. This one is like react's one, basically.
    */
    render() {
        const {age, name, children} = this.props;
        return dom('h1', {style: {color: 'red'}}, [`${name}: ${age}`,
            ...children
        ]);
    }
}

Stateless Components

Not all components need acccess to the state or need to know whenever they should update. Some are simply a modular way to handle common usage of HTML nodes. Just like react, you can export an arrow function that gets its props as its single parameter, and returns the dom tree:

const {dom} = require('xow');
 
module.exports = ({text}) => (
    <div>
        <p>{text}!</p>
    </div>
);

renderTo

Finally, we want to mount our app to the document, so let's just:

// app.js
 
const {renderTo, dom} = require('xow');
const Main = require('./components/main');
 
renderTo(document.getElementById('container'), dom(Main, {}, [
    dom('p', {}, 'Hello, world!')
]));

And TADA! You have a running xow app. For actual reactive features please take a look at the link above.

JSX-enablers

To enable JSX, you're gonna need babel and its babel-plugin-transform-react-jsx. Use the following .babelrc snippet:

plugins: [
    ["transform-react-jsx", {
      "pragma": "dom"
    }]
]

Here's main.js above, JSX style:

// components/main.js
 
const App = require('./base');
const {pipe, link} = require('xain');
const {dom, children} = require('xow');
 
module.exports = class Main extends App {
    static view() {
        return {
            age: 'age',
            name({firstName, lastName}) {
                return `${firstName} ${lastName}`;
            }
        }
    }
    render() {
        const {age, name} = this.props;
        return (
            <h1 style={{color: 'red'}}>
                {name}: {age}
                {...this.props.children}
            </h1>
        );
    }
}

Complex Components

When creating a compnent with props which should be derived from 2 or more state trees, you can use ComplexComponent, which is a lot like the Component class factory, only it accets ...states instead of state as a parameter, its view function is called reaction, it is passed the same ...states passed to the factory, in the same order, and it returns the spec for a xain reactive object, using the regular pipe and link values.