React Hardware

React Hardware enables you to build firmata-based hardware applications using a consistent developer experience based on JavaScript and React. The focus of React Hardware is on developer efficiency across all the platforms you care about - learn once, write anywhere.

React Hardware is a IoT and Robotics programming framework developed by Dustan Kasten. Being based on firmata, it is capable of providing feature parity with alternative tools such as Johnny-Five.

Note that this is currently alpha software and hasn’t been tested or have many features implemented. It currently supports firmata’s digitalWrite and analogWrite methods. Full support for firmata is coming including an event system to receive feedback from the board and manipulate state as a result of that.

Hello World

The "Hello World" program of microcontrollers is to "blink an LED". The following code demonstrates how this is done naively with React Hardware and how React’s programming model brings composability to the hardware world.

import React from 'react';
import ReactHardware, {Led} from 'react-hardware';

const HIGH = 255;
const LOW = 0;

class Application extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: 0};
    this._timer = null;
  }

  componentDidMount() {
    this._timer = setInterval(_ => (
      this.setState(prevState => ({value: prevState.value === HIGH ? LOW : HIGH}))
    ), this.props.interval);
  }

  componentWillUnmount() {
    clearInterval(this._timer);
    this._timer = null;
  }

  render() {
    return (
      <Led pin={10} value={this.state.value} />
    );
  }
}

var PORT = '/dev/tty.usbmodem1411';
ReactHardware.render(<Application interval={1000} />, PORT);

While this is unquestionably more code than it’s Johnny-Five or Sketch equivalents, this now gives you the ability to extract the parts of your board into self-contained components and compose these together. In this application we introduced the concept of a flashing LED, hard-coded naively into the global state. Let’s now extract the idea of a flashing LED into something we can share with our team or even on npm.

import React from 'react';
import ReactHardware, {Board, Led} from 'react-hardware';

const HIGH = 255;
const LOW = 0;

class FlashingLed extends React.Component {
  constructor(props) {
    super(props);
    this.state = {value: 0};
    this._timer = null;
    this.defaultProps = {
      interval: 1000,
    };
  }

  componentDidMount() {
    this._timer = setInterval(_ => (
      this.setState(prevState => ({value: prevState.value === HIGH ? LOW : HIGH}))
    ), this.props.interval);
  }

  componentWillUnmount() {
    clearInterval(this._timer);
    this._timer = null;
  }

  render() {
    return (
      <Led {...this.props} value={this.state.value} />
    );
  }
}

class Application extends React.Component {
  render() {
    return (
      <Board>
        <FlashingLed pin={9} />
        <FlashingLed pin={10} />
        <FlashingLed pin={11} />
        <FlashingLed pin={12} />
      </Board>
    );
  }
}

var PORT = '/dev/tty.usbmodem1411';
ReactHardware.render(<Application />, PORT);

Community

There should be #react-hardware channels created on both https://reactiflux.com/ and IRC.

Contributing

The codebase is written in es6 with (sporadic) types and compiled with babel. Follow the existing style when creating changes. Eslint and the flow type checker will be set up shortly. While the project is under heavy active development it would be useful to make an issue discussing your change before making a PR to ensure we aren’t duplicating effort.

License

Copyright (c) 2015 Dustan Kasten | [email protected] Licensed under the MIT license.