@dotfold/rx-react

RxReact

ReactJS bindings for RxJS

Installation

Install this module with npm:

npm install rx-react

Usage:

RxReact provides a set of utilities to work with RxJS and React :

• The StateStreamMixin
• The LifecycleMixin
• The PropsMixin
• The RxReact.Component base class
• The FuncSubject helper

StateStreamMixin

The StateStreamMixin allows to bind a component state to an RxJS Observable stream. The way to achieve the binding is to provide a getStateStream method on your component that returns an RxJS Observable, the StateStream mixin will automatically merge the state of your component with the values published by the returned observable. The subscription will be automaticly cleaned on component unmount.

Example:

var StateStreamMixin = require('rx-react').StateStreamMixin;
var React = require('react');
var Rx = require('rx');


var Timer = React.createClass({
  mixins: [StateStreamMixin],
  getStateStream: function () {
    return Rx.Observable.interval(1000).map(function (interval) {
      return {
        secondsElapsed: interval
      };
    });
  },
  render: function () {
    var secondsElapsed = this.state ? this.state.secondsElapsed : 0;
    return (
      <div>Seconds Elapsed: {secondsElapsed}</div>
    );
  }
});

React.render(<Timer />, document.getElementById('timer-holder'));

LifecycleMixin

The LifecycleMixin allows you to consume React components lifecycle events as RxJS Observable. The LifecycleMixin will inject a property lifecycle to the component, that property contains an observable for each lifecycle events.

Example :

var LifecycleMixin = require('rx-react').LifecycleMixin;
var React = require('react');
var Rx = require('rx');


var Component = React.createClass({
  mixins: [LifecycleMixin],
  componentWillMount: function () {
    this.lifecycle.componentDidMount.subscribe(function () {
      console.log('componentDidMount');
    });
    
    this.lifecycle.componentWillReceiveProps.subscribe(function (props) {
      console.log('componentWillReceiveProps : ' JSON.stringify(props));
    });
    
    this.lifecycle.componentWillUpdate.subscribe(function ({nextProps, nextState}) {
      console.log('componentWillUpdate : ' JSON.stringify({nextProps, nextState}));
    });
    
    this.lifecycle.componentDidUpdate.subscribe(function ({prevProps, prevState}) {
      console.log('componentDidUpdate : ' JSON.stringify({prevProps, prevState}));
    });
    this.lifecycle.componentWillUnmount.subscribe(function () {
      console.log('componentWillUnmount');
    });
  },
  render: function() {
    //...
  }
});

PropsMixin

The PropsMixin allows to obtain a stream of props as RxJS Observable for your component. Example :

var PropsMixin = require('rx-react').PropsMixin;
var React = require('react');


var Component = React.createClass({
  mixins: [PropsMixin],
  componentWillMount: function () {
    this.propsStream.subscribe(function (props) {
      console.log(props.message);
    }
  },
  render: function() {
    //...
  }
});

var comp = React.render(<Component message='Hello World!' />, domNode); // log 'Hello World!'
comp.setProps({message: 'Hello John'}); // log 'Hello John'

This is particulary useful in combination with the StateStreamMixin when your component states depends on Props.

Component

The RxReact.Component is a base class combining the behavior of the PropsStreamMixin and the StateStreamMixin. It extends React.Component. Example:

var RxReact = require('rx-react');
var Rx = require('rx');

class MyComponent extends RxReact.Component {
  getStateStream() {
    return Rx.Observable.interval(1000).map(function (interval) {
      return {
        secondsElapsed: interval
      };
    });
  }
  
  render() {
    var secondsElapsed = this.state ? this.state.secondsElapsed : 0;
    return (
      <div>Seconds Elapsed: {secondsElapsed}</div>
    );
  }
}

Note that when you extend lifecycle methods, you must call the super method.

Before the 0.3.x versions RxReact.Component also implemented lifecyle mixin behavior, for some perf reasons and because most of the time it's unnecessary this has been removed. If you want reenable this behavior use FuncSubject as lifecycle method, or manually apply the LifecycleMixin on your class.

FuncSubject

The FuncSubject helper allows to create an RxJS Observable that can be injected as callback for React event handlers, refs, etc... To create an handler use the create function of FuncSubject

var myHandler = FuncSubject.create()

Example:

var FuncSubject = require('rx-react').FuncSubject;
var React = require('react');
var Rx = require('rx');


var Button = React.createClass({
  componentWillMount: function () {
    this.buttonClicked = FuncSubject.create();
    
    this.buttonClicked.subscribe(function (event) {
      alert('button clicked');
    })
  },
  render: function() {
    return <button onClick={this.buttonClicked} />
  }
});

FuncSubject also accept a function as argument, if provided this funtion will be used to map the value of each elements. This function will always be called even if the FuncSubject has no subscription.

var FuncSubject = require('rx-react').FuncSubject;
var React = require('react');
var Rx = require('rx');


var MyComponent = React.createClass({
  componentWillMount: function () {
    this.inputValue = FuncSubject.create(function (event) {
      return event.target.value
    });
    
    this.inputValue.subscribe(function (value) {
      alert('inputValue changed :' + value);
    })
  },
  render: function() {
    return <input onChange={this.inputValue} />
  }
});

FuncSubject.behavior

You can also create a FuncSubject that extends BehaviorSubject. simply use the behavior function exposed by FuncSubject:

var subject = FuncSubject.behavior(intialValue, mapFunction)

FuncSubject.async

You can also create a FuncSubject that extends AsyncSubject. simply use the async function exposed by FuncSubject:

var subject = FuncSubject.async(mapFunction)

FuncSubject.replay

You can also create a FuncSubject that extends ReplaySubject. simply use the replay function exposed by FuncSubject:

var subject = FuncSubject.replay(bufferSize, mapFunction)

FuncSubject.replay

You can create a FuncSubject from any subject base class using the factory function expsed by FuncSubject:

var subject = FuncSubject.factory(SubjectClass, mapFunction, ...constructorArgs);