initialization.md

Initialization Options

Explicit Init Transition

By default, if you don't specify an initial state, the state machine will be in the none state, no lifecycle events will fire during construction, and you will need to provide an explicit transition to advance out of this state:

  var fsm = new StateMachine({
    transitions: [
      { name: 'init', from: 'none', to: 'A' },
      { name: 'step', from: 'A',    to: 'B' },
      { name: 'step', from: 'B',    to: 'C' }
    ]
  });
  fsm.state;    // 'none'
  fsm.init();   // 'init()' transition is fired explicitly
  fsm.state;    // 'A'

Implicit Init Transition

If you specify the name of your initial state (as in most of the examples in this documentation), then an implicit init transition will be created for you and fired (along with appropriate lifecycle events) when the state machine is constructed.

This is the most common initialization strategy, and the one you should use 90% of the time

  var fsm = new StateMachine({
    init: 'A',
    transitions: [
      { name: 'step', from: 'A', to: 'B' },
      { name: 'step', from: 'B', to: 'C' }
    ]
  });           // 'init()' transition fires from 'none' to 'A' during construction
  fsm.state;    // 'A'

Initialization and State Machine Factories

For State Machine Factories, the init transition is triggered for each constructed instance.

  var FSM = StateMachine.factory({
    init: 'A',
    transitions: [
      { name: 'step', from: 'A', to: 'B' },
      { name: 'step', from: 'B', to: 'C' }
    ]
  });

  var fsm1 = new FSM(),   // 'init()' transition fires from 'none' to 'A' for fsm1
      fsm2 = new FSM();   // 'init()' transition fires from 'none' to 'A' for fsm2