stateflowjs

simple state machine to create work flow in vanilla js

Usage

const StateFlow = require('StateFlow')

const mainFsm = new StateFlow(options)

// to start start machine
mainFsm.start();

Options

options is an object

options.name

the state machine name. name is a string, default value "unknown".

options.initialstate

initial state of the state machine. when start method involved, state machine start from initial state.

options.states

states is an object, included state machine's states.

Methods

isRunning

return true if state machine is running, else return false.

start[parent, ...payloads]

parent

parent state machine of the state machine, default null, if state machine start in an other state machine, parent state machine will set.

const childFsm = new StateFlow({
  name: "child",
  initialstate: "uninitialized",
  states:{
    "uninitialized": {
      onEnter: () => {
        
      }
    }
  }
})

const parentFsm = new StateFlow({
  name: "parent",
  initialstate: "uninitialized",
  states:{
    "uninitialized": {
      onEnter: () => {
        childFsm.start(this)
      }
    }
  }
})

parentFsm.start()

payloads

payloads for the initial state.

stop[parentAction, ...payload]

stop the state machine. if parent action is exist, handle the parent action with payloads.

transition[to, ...payload]

transition to state with payloads.

getCurrentState

return the current state.

handle[action, ...payloads]

hendle the action of the state with payloads, if the state has the given action.

Events

action_handled

when action handled.

started

when state machine started.

already_running

error

transition

Event publishing

const fsm = new StateFlow({
  states: {
    "state": function() {
      this.emit("event_name")
    }
  }
})

Example

Atm

const StateFlow = require('../../src/StateFlow')

const Atm = new StateFlow({
  name: 'Atm',
  intialstate: 'uninitialized',
  states: {
    'uninitialized': {
      onEnter: function () {
        this.handle('initialize')
      },
      'initialize': function (pl) {
        // TODO: any other init work here...
        this.acct = null
        this.balance = 15
        this.emit('initialized')
        this.transition('unauthorized')
      }
    },

    'unauthorized': {
      onEnter: function () {
        this.emit('unauthorized', { msg: 'please enter your account and PIN' })
      },
      authorize: function (credentials) {
        if (credentials.acct === 'x' && credentials.pin === 'x') {
          this.acct = 'x'
          this.transition('authorized')
        } else {
          this.emit('unauthorized', { msg: 'invalid credentials' })
        }
      }
    },

    'authorized': {
      onEnter: function () {
        this.emit('authorized', { acct: this.acct })
      },
      deposit: function (amount) {
        this.balance += amount
        this.emit('deposit', { result: 'success', balance: this.balance })
      },
      withdrawal: function (amount) {
        if (this.balance - amount > -1) {
          this.balance -= amount
          this.emit('withdrawal', { result: 'success', balance: this.balance })
        } else {
          this.emit('withdrawal', { result: 'insufficient balance', balance: this.balance })
        }
      },
      deauthorize: function () {
        this.acct = null
        this.transition('unauthorized')
      }
    }
  }
})

Atm.on('initialized', () => {
  console.log('Atm initialized')
})

Atm.on('unauthorized', (o) => {
  console.log('ATM unauthorized! ' + o.msg)
  Atm.handle('authorize', { acct: 'x', pin: 'x' })
})

Atm.on('authorized', (o) => {
  console.log('Authorized acct: ' + o.acct)
  Atm.handle('deposit', 5)
})

Atm.on('deposit', (result) => {
  console.log(result)
  Atm.handle('withdrawal', 15)
})

Atm.on('withdrawal', (result) => {
  console.log(result)
})

Atm.start()

module.exports = Atm