zhangbowei/state.js

Hierarchical finite state machine for node and web browsers

Executable state machine for Node and Web development.

If you like state.js, please star it.

Update: state.js is now available via Bower

Getting started

The state.js API is split into:

1. Classes that represent a state machine model (State, PseudoState, Transition, etc.)
2. An interface and implementation of active state configuration (current state); this allows multiple concurrent instances of a single state machine model
3. A set of functions that provide the state machine runtime

The API is bound to a global object of your choosing.

state.js is developed in TypeScript and transpiled to JavaScript; you can use it in either language.

Node

1. Install state.js in your project:

$ npm install state.js

2. Import state.js and build your state machine:

var state = require("state.js");

// send log messages, warnings and errors to the console
state.console = console;

// create the state machine model elements
var model = new state.StateMachine("model");
var initial = new state.PseudoState("initial", model, state.PseudoStateKind.Initial);
var stateA = new state.State("stateA", model);
var stateB = new state.State("stateB", model);

// create the state machine model transitions
initial.to(stateA);
stateA.to(stateB).when(function (message) { return message === "move"; });

// create a state machine instance
var instance = new state.StateMachineInstance("instance");

// initialise the model and instance
state.initialise(model, instance);

// send the machine instance a message for evaluation, this will trigger the transition from stateA to stateB
state.evaluate(model, instance, "move");

Web

1. Add state.js to your project:

$ bower install --save state

Alternatively, download direct from lib/state.js or lib/state.min.js.

2. Include state.js as a script in your page:

<script type="text/javascript" src="/bower_components/state/lib/state.min.js" target="state"></script>

Note: the target attribute within the script element defines the name of the global object that the state.js API will be bound to. If not specified, state.js will be bound to window.fsm.

3. Create your state machine in another script:

<script>
	// send log messages, warnings and errors to the console
	state.console = console;

	// create the state machine model elements
	var model = new state.StateMachine("model");
	var initial = new state.PseudoState("initial", model, state.PseudoStateKind.Initial);
	var stateA = new state.State("stateA", model);
	var stateB = new state.State("stateB", model);

	// create the state machine model transitions
	initial.to(stateA);
	stateA.to(stateB).when(function (message) { return message === "move"; });

	// create a state machine instance
	var instance = new state.StateMachineInstance("test");

	// initialise the model and instance
	state.initialise(model, instance);

	// send the machine instance a message for evaluation, this will trigger the transition from stateA to stateB
	state.evaluate(model, instance, "move");
</script>

Versioning

The versions are in the form {major}.{minor}.{build}

• Major changes introduce significant new behavior and will update the public API.
• Minor changes introduce features, bug fixes, etc, but note that they also may break the public API.
• Build changes can introduce features, though usually are fixes and performance enhancements; these will never break the public API.

Documentation

Documentation for the public API can be found here.

Licence

state.js is dual-licenecd under the MIT and GPL v3 licences.