Javascript State Machine

A javascript finite state machine library

Description

A library for finite state machines.

Programming language: JavaScript

License: MIT License

Tags: MVC Frameworks And Libraries     Derby     Workflow     Finite State Machine     FSM     State Machine    

Latest version: v3.1.0

README

Javascript State Machine

A library for finite state machines.

[matter state machine](examples/matter.png)

NOTE for existing users

VERSION 3.0 Is a significant rewrite from earlier versions. Existing 2.x users should be sure to read the [Upgrade Guide](docs/upgrading-from-v2.md).

Installation

In a browser:

  <script src='state-machine.js'></script>

after downloading the [source](dist/state-machine.js) or the [minified version](dist/state-machine.min.js)

Using npm:

  npm install --save-dev javascript-state-machine

In Node.js:

  var StateMachine = require('javascript-state-machine');

Usage

A state machine can be constructed using:

  var fsm = new StateMachine({
    init: 'solid',
    transitions: [
      { name: 'melt',     from: 'solid',  to: 'liquid' },
      { name: 'freeze',   from: 'liquid', to: 'solid'  },
      { name: 'vaporize', from: 'liquid', to: 'gas'    },
      { name: 'condense', from: 'gas',    to: 'liquid' }
    ],
    methods: {
      onMelt:     function() { console.log('I melted')    },
      onFreeze:   function() { console.log('I froze')     },
      onVaporize: function() { console.log('I vaporized') },
      onCondense: function() { console.log('I condensed') }
    }
  });

... which creates an object with a current state property:

• fsm.state

... methods to transition to a different state:

• fsm.melt()
• fsm.freeze()
• fsm.vaporize()
• fsm.condense()

... observer methods called automatically during the lifecycle of a transition:

• onMelt()
• onFreeze()
• onVaporize()
• onCondense()

... along with the following helper methods:

• fsm.is(s) - return true if state s is the current state
• fsm.can(t) - return true if transition t can occur from the current state
• fsm.cannot(t) - return true if transition t cannot occur from the current state
• fsm.transitions() - return list of transitions that are allowed from the current state
• fsm.allTransitions() - return list of all possible transitions
• fsm.allStates() - return list of all possible states

Terminology

A state machine consists of a set of [States](docs/states-and-transitions.md)

• solid
• liquid
• gas

A state machine changes state by using [Transitions](docs/states-and-transitions.md)

• melt
• freeze
• vaporize
• condense

A state machine can perform actions during a transition by observing [Lifecycle Events](docs/lifecycle-events.md)

• onBeforeMelt
• onAfterMelt
• onLeaveSolid
• onEnterLiquid
• ...

A state machine can also have arbitrary [Data and Methods](docs/data-and-methods.md).

Multiple instances of a state machine can be created using a [State Machine Factory](docs/state-machine-factory.md).

Documentation

Read more about

• [States and Transitions](docs/states-and-transitions.md)
• [Data and Methods](docs/data-and-methods.md)
• [Lifecycle Events](docs/lifecycle-events.md)
• [Asynchronous Transitions](docs/async-transitions.md)
• [Initialization](docs/initialization.md)
• [Error Handling](docs/error-handling.md)
• [State History](docs/state-history.md)
• [Visualization](docs/visualization.md)
• [State Machine Factory](docs/state-machine-factory.md)
• [Upgrading from 2.x](docs/upgrading-from-v2.md)

Contributing

You can [Contribute](docs/contributing.md) to this project with issues or pull requests.

Release Notes

See [RELEASE NOTES](RELEASE_NOTES.md) file.

License

See MIT LICENSE file.

Contact

If you have any ideas, feedback, requests or bug reports, you can reach me at [email protected], or via my website: Code inComplete