mecha-ts

finished state machine using typescript

mecha-ts

mecha-ts is a 0-dependency finished state machine ts compatible

Installation

Download nodejs first. Use npm to install get-ip-from-request.

npm i mecha-ts@latest

Usage

// machine.js
import { createMachine, guard, intermediate, reduce, state, transition } from "mecha-ts"

const STATES = Object.freeze({
  LOGIN_SCREEN: 0,
  HUB_SCREEN: 1,
  GAME_SCREEN: 2
})

const EVENTS = Object.freeze({
  LOGIN: 0,
  LOGOUT: 1,
  JOIN: 2,
  PLAY: 3,
  LEAVE: 4,
  END_GAME: 5
})

const makeCtx = () => ({
  pseudo: '',
  room: '',
  life: 0,
  x: 0,
  y: 0
})
// guard
const validPseudo = (ctx, e) => ctx?.pseudo !== e?.payload?.pseudo
const endGame = (ctx) => ctx?.life === 0
// reducer
const login = (ctx, e) => ({ ...ctx, pseudo: e?.payload?.pseudo ?? '' })
const initGame = (ctx) => ({ ...ctx, life: 3, x: 10, y: 10 })
const leaveGame = (ctx) => ({ ...ctx, life: 0, x: 0, y: 0, room: '' })
const play = (ctx, e) => ({
  ...ctx,
  life: e?.payload?.life,
  x: e?.payload?.x,
  y: e?.payload?.y
})

const MyMachine = createMachine([
  state(
    STATES.LOGIN_SCREEN,
    intermediate(EVENTS.LOGIN, guard(validPseudo), STATES.HUB_SCREEN, STATES.LOGIN_SCREEN, reduce(login))
  ),
  state(
    STATES.HUB_SCREEN,
    transition(EVENTS.LOGOUT, STATES.LOGIN_SCREEN, reduce(makeCtx)),
    transition(EVENTS.JOIN, STATES.GAME_SCREEN, reduce(initGame))
  ),
  state(
    STATES.GAME_SCREEN,
    transition(EVENTS.LEAVE, STATES.HUB_SCREEN, reduce(leaveGame)),
    transition(EVENTS.PLAY, STATES.GAME_SCREEN, reduce(play)),
    transition(EVENTS.END_GAME, STATES.GAME_SCREEN, reduce(initGame), guard(endGame))
  )
], makeCtx)

export { MyMachine }

Important

mecha-ts is inspired by robot3 but mecha-ts and robot3 has some differences :

• mecha-ts use number for identify states and events, robot3 accept only string
• robot3 use invoke for async transition, mecha-ts haven't

Contributing

...

License

MIT