Redux Spirit

Statechart middleware for Redux using SCION-CORE

Why?

Redux is great for data state management, however managing application state is still the developer's responsibility. Redux Spirit uses the approach presented in David Harel's paper Statecharts: a visual formalism for complex systems.

Installation

npm i --save redux-spirit

Redux Spirit is used as a Redux middleware:

import {createStore, applyMiddleware} from 'redux'
import {reduxSpirit} from 'redux-spirit'

import {reducer} from './reducer'

// Minimal statechart
const statechart = {
  id: 'MAIN',
}

const store = createStore(
  reducer,
  applyMiddleware(reduxSpirit(statechart)),
)

API

reduxSpirit(<Object|Array> statechart, <Object> options): null

statechart (required)

Object or Array of Objects declaring SCION-CORE's Statecharts Model Schema

options (not required)

name	type	default	description
log	bool	false	Logs state changes and transactions
verbose	bool	false	More verbose logging of following SCION-CORE events: onBigStepBegin onBigStepEnd onSmallStepBegin onSmallStepEnd

onEntry(<String> stateId): <String> actionType

Action type dispatched after entering state with stateId

onExit(<String> stateId): <String> actionType

Action type dispatched after exiting state with stateId

onTransition(<String> eventId): <String> actionType

Action type dispatched on transition with eventId

onEntry(), onExit(), and onTransition() are helper methods for generating action types. Can be used in reducer or by handling Api calls.

Example with Redux's reducer:

import {onEntry, onExit, onTransition} from 'redux-spirit'

const states = {
  INIT: 'INIT',
  LOADING: 'LOADING',
}

const events = {
  FETCH: 'FETCH',
}

const reducer = (state, action) => {
  switch(action.type) {
    case onEntry(states.LOADING):
      // action.type: 'a:entry:LOADING'
      return {/* new state */}
      
    case onExit(states.INIT):
      // action.type: 'a:exit:INIT'
      return {/* new state */}
      
    case onTransition(events.FETCH):
      // action.type: 'a:transition:FETCH'
      return {/* new state */}
      
    default:
      return state
  }
}