data-and-methods.md

Data and Methods

In addition to States and Transitions, a state machine can also contain arbitrary data and methods:

  var fsm = new StateMachine({
    init: 'A',
    transitions: [
      { name: 'step', from: 'A', to: 'B' }
    ],
    data: {
      color: 'red'
    },
    methods: {
      describe: function() {
        console.log('I am ' + this.color);
      }
    }
  });

  fsm.state;      // 'A'
  fsm.color;      // 'red'
  fsm.describe(); // 'I am red'

Data and State Machine Factories

If you are constructing multiple instances from a State Machine Factory then the data object will be shared amongst them. This is almost certainly NOT what you want! To ensure that each instance gets unique data you should use a data method instead:

  var FSM = StateMachine.factory({
    init: 'A',
    transitions: [
      { name: 'step', from: 'A', to: 'B' }
    ],
    data: function(color) {      //  <-- use a method that can be called for each instance
      return {
        color: color
      }
    },
    methods: {
      describe: function() {
        console.log('I am ' + this.color);
      }
    }
  });

  var a = new FSM('red'),
      b = new FSM('blue');

  a.state; // 'A'
  b.state; // 'A'

  a.color; // 'red'
  b.color; // 'blue'

  a.describe(); // 'I am red'
  b.describe(); // 'I am blue'

NOTE: that arguments used when constructing each instance are passed thru to the data method directly.