ivy-stateful

Simple State Machines for Ember apps, based on Ember Data's DS.Model state machine.

Installation

For Ember CLI >= 0.2.3:

ember install ivy-stateful

For Ember CLI 0.1.5 through 0.2.2:

ember install:addon ivy-stateful

For Ember CLI < 0.1.5:

npm install --save-dev ivy-stateful

Usage

This addon provides a StatefulMixin mixin that makes any Ember.Object into a finite state machine. After mixing it in, you'll need to define a rootState to serve as the root of your state machine, as well as an initialState which will be transitioned into immediately.

Here's the obligatory Vechicle example:

import Ember from 'ember';
import StatefulMixin from 'ivy-stateful/mixins/stateful';

export default Ember.Object.extend(StatefulMixin, {
  initialState: 'parked',

  speed: Ember.computed.readOnly('currentState.speed'),

  rootState: {
    speed: 0,

    parked: {
      enter: function(vehicle) {
        vehicle.takeOffSeatbelt();
      },

      exit: function(vehicle) {
        vehicle.putOnSeatbelt();
      },

      ignite: function(vehicle) {
        vehicle.transitionTo('idling');
      }
    },

    idling: {
      shiftUp: function(vehicle) {
        vehicle.transitionTo('firstGear');
      }
    },

    firstGear: {
      speed: 10,

      idle: function(vehicle) {
        vehicle.transitionTo('idling');
      }
    }
  },

  putOnSeatbelt: function() {
    this.set('seatbeltOn', true);
  },

  takeOffSeatbelt: function() {
    this.set('seatbeltOn', false);
  }
});

You can use send to send events to the current state:

vehicle.get('seatbeltOn') // => false
vehicle.send('ignite');   // puts us in the "idling" state
vehicle.get('seatbeltOn') // => true
vehicle.send('shiftUp');  // puts us in the "firstGear" state
vehicle.get('speed')      // => 10

The receiver (the vehicle in this case) is always the first argument to an event handler, followed by any other arguments passed to send.

If you just want an isolated state machine, ivy-stateful provides one in the form of the StateMachine class.

import StateMachine from 'ivy-stateful/state-machine';

export default StateMachine.extend({
  initialState: 'initial',

  rootState: {
    // ...
  }
});

The StateMachine class is just Ember.Object with StatefulMixin already applied for you.

Running

• ember server
• Visit your app at http://localhost:4200.

Running Tests

• ember test
• ember test --server

Building

• ember build

For more information on using ember-cli, visit http://www.ember-cli.com/.