https://github.com/patbenatar/promise-state-machine

An event-driven finite state machine backed by Promises
https://github.com/patbenatar/promise-state-machine

Last synced: 2 months ago
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An event-driven finite state machine backed by Promises

• Host: GitHub
• URL: https://github.com/patbenatar/promise-state-machine
• Owner: patbenatar
• License: mit
• Created: 2015-03-22T20:35:07.000Z (almost 10 years ago)
• Default Branch: master
• Last Pushed: 2017-09-11T19:41:20.000Z (over 7 years ago)
• Last Synced: 2024-09-22T15:10:51.105Z (4 months ago)
• Language: JavaScript
• Size: 10.7 KB
• Stars: 8
• Watchers: 3
• Forks: 3
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • License: LICENSE.md

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README

        
# Promise State Machine

[![npm version](https://badge.fury.io/js/promise-state-machine.svg)](http://badge.fury.io/js/promise-state-machine)

[![Code Climate](https://codeclimate.com/github/patbenatar/promise-state-machine/badges/gpa.svg)](https://codeclimate.com/github/patbenatar/promise-state-machine)

[![Test Coverage](https://codeclimate.com/github/patbenatar/promise-state-machine/badges/coverage.svg)](https://codeclimate.com/github/patbenatar/promise-state-machine)

```javascript

var fsm = new PromiseStateMachine({

  initial: 'green',

  events: {

    warn: { from: 'green', to: 'yellow' },

    panic: { from: ['green', 'yellow'], to: 'red' },

    calm: { from: 'red', to: 'yellow' },

    clear: { from: ['yellow', 'red'], to: 'green' }

  }

});

fsm.on('warn', function(event, from, to, anyArgs) {

  return Promise.resolve('result 1');

});

fsm.on('warn', function(event, from, to, anyArgs) {

  var transaction = anyArgs[0];

  var somethingElse = anyArgs[1];

  return Promise.resolve('result 2');

});

fsm.warn(transaction, somethingElse).then(function(results) {

  // results: ['result 1', 'result 2']

}).error(function(error) {

  // could receive a StateTransitionError if trying to transition via an

  // inaccessible event.

});

fsm.is('green'); // => false

fsm.is('yellow'); // => true

fsm.state(); // => 'yellow'

fsm.can('calm'); // => false

fsm.can('panic'); // => true

```

## Extending an existing object

```javascript

var MyObject = function() {

  PromiseStateMachine.call(this, {

    initial: 'green',

    events: {

      warn: { from: 'green', to: 'yellow' },

      panic: { from: 'yellow', to: 'red' },

      calm: { from: 'red', to: 'yellow' },

      clear: { from: 'yellow', to: 'green' }

    }

  });

};

_.extend(MyObject, PromiseStateMachine);

_.extend(MyObject.prototype, PromiseStateMachine.prototype);

var fsm = new MyObject();

fsm.is('green'); // => true

fsm.warn().then(function() {

  fsm.is('green'); // => false

});

```