abstract-things

abstract-things

abstract-things is a JavaScript library that provides a simple base for building libraries that interact with physical things, such as IoT-devices, and virtual things.

This library provides a base class named Thing that supports mixins of various types. Things are described using two types of tags, one describing the type of the thing and one describing its capabilities. Things are also expected to describe their public API, to make remote use easier.

Types and capabilities are designed to be stable and to be combined. When combined they describe a thing and what it can do.

Detailed documentation is available at: http://abstract-things.readthedocs.io/en/latest/

Building a simple thing

npm install abstract-things

A basic thing might look a bit like this:

const { Thing } = require('abstract-things');

class SimpleThing extends Thing {
  // Define the type of the thing
  static get type() {
    return 'simple-thing';
  }

  // Quick way to define actions available for this thing
  static get availableAPI() {
    return [ 'hello' ];
  }

  constructor() {
    super();

    // An identifier of the thing should always be set - with a namespace
    this.id = 'thing:example-1';
  }

  hello() {
    return 'Cookies are tasty';
  }
}

console.log(new SimpleThing());

Identifiers and namespaces

Identifiers are required when bulding a thing. They should uniquelly identify the thing and if possible remain stable over time. In addition that that a thing should also belong to a namespace. Namespaces are used to make ids unique when several thing-libraries are used. Namespaces should be short and related to the type of thing, such as hue for Philips Hue lights or bluetooth for Bluetooth peripherals.

Types and capabilities

Types are used to describe what a thing is and capabilities describe what a thing can do. A thing can have many capabilities but usually its only a few types.

This library includes a set of capabilities and types that are intended to cover many common appliances and devices. Information about these can be found in the detailed documentation.

Using a capability

Pre-defined capabilities can simply be mixed in when creating a thing:

const { Thing, State } = require('abstract-things');

class MyThing extends Thing.with(State) {
  constructor() {
    super();

    this.updateState('key', 'value');
  }
}

Defining a capability

To create a reusable capability you can create a mixin using the Thing.capability function:

const { Thing } = require('abstract-things');

module.exports = Thing.capability(BaseThing => class extends BaseThing {
  
  // Tell clients about this capability
  static get capability() {
    return 'cookie-monster';
  }

  // Tell clients about our API
  static availableAPI(builder) {
    builder.action('nom')
      .description('Eat a cookie')
      .argument('string', false, 'The type of cookie to eat')
      .done();
  }
  
  constructor(...args) {
    super(...args);
  }

  nom(cookieType) {
    return 'Ate cookie of type ' + cookieType;
  }
});