Zetta Device Module

Install

$ npm install zetta-device --save

Reference and Usage

Class: Zetta.Device

This is a zetta device modeled in software. With zetta you can create state machines for all of your devices that conditionally allow functionality to be exposed based on the state property. You should inherit from this class and implement the init function require('zetta-device'); or require('zetta').Device;.

var util = require('util');
var Device = require('zetta-device');

function MyDevice(){
  Device.call(this);
}
util.inherits(MyDevice, Device);

Property: Device#state

This is the current state of your device modeled in software.

Method: Device#init(config)

• config DeviceConfig

This method should be implemented by you. The argument config is a configuration object that will allow you to setup your state machine, name your object, and give it a type.

MyDevice.prototype.init = function(config) {
  config
    .type('device')
    .state('on')
    .name('CoolDevice')
};

Method: Device#available(transition)

• transition String

Check if a transition is available for use on the current device.

if(device.available('turn-on')) {
  //turn-on transition available
}

Method: Device#call(name, [arguments...], callback)

• name String
• arguments Arguments for the transition.
• callback Function

This method will call a transition on your state machine. You supply a splat fo additional arguments if required by the implementation of the particular transition. An optional callback can be provided as well. Callback is called once the state transition is complete.

device.call('change-color', '#FF0000', function(err){
  if(err) {
    console.log('Color change error');
  }
});

Method: Device#save

Save the device in it's current state to the zetta device registry.

device.save();

Method: Device#createReadStream(name)

• name String

Create an instance of a readable stream of values from the name of the stream.

var volumeStream = microphone.createReadStream('volume');

Method: DeviceConfig#when(state, options)

• state String
• options Object

The when method on device config allows you to set what transitions are available in a particular state. The first argument of state should be a valid state for the object, and the second takes an options object with a property called allow where you can define the available transitions for the state.

MyDevice.prototype.init = function(config) {
  config
    .when('on', {allow: ['off']})
};

This method will conditionally set available transitions for your state machine based on the state property.

Method: DeviceConfig#map(transition, func, [options])

• transition String
• func Function
• options Array of Object

This method allows you to map transitions to functions. Whenever a transition is called on a state machine the corresponding function will be executed. The options array is where inputs to the transition are defined.

MyDevice.prototype.init = function(config) {
  config
    .map('on', this.turnOn);
    .map('strobe', this.strobe, [{name:'amount', type:'number'}])
};

MyDevice.prototype.turnOn = function(cb) {

};

MyDevice.prototype.strobe = function(amount, cb ){

};

Method: DeviceConfig#stream(name, func, [options])

• name String
• func Function
• options Object

stream will allow for setting up streaming data out of zetta. The first argument name is to identify the stream, the second argument func is a callback function that is executed to provide a user with a stream. The third argument options will allow a user to define the type of stream to be created object or binary

MyDevice.prototype.init = function(config) {
  config
    .stream('value', this.streamValue);
};

MyDevice.prototype.streamValue = function(stream) {
  setInterval(function(){
    stream.write(Math.random());
  }, 3000);
}

Method: DeviceConfig#monitor(name)

• name String

Stream a property from your device instance out of zetta. Zetta will monitor the property for changes, and if they occur will publish an event down the stream.

function MyDevice() {
  this.blah = 0;
}

MyDevice.prototype.init = function(config) {
  config
    .monitor('blah');
}