Generated by XState Viz: https://xstate.js.org/viz

machine.js

const State = {
  GREEN: "GO",
  OFFLINE: "OFFLINE",
  RED: "STOP",
  UNKNOWN: "UNKNOWN",
  YELLOW: "YELLOW",
};

const Event = {
  CHANGE: "CHANGE",
  MAINTENANCE_END: "MAINTENANCE_END",
  MAINTENANCE_START: "MAINTENANCE_START",
  OUTAGE: "OUTAGE",
  RESTORED: "RESTORED",
};

const Action = {
  GREEN_ENTERED: "GREEN_ENTERED",
  GREEN_EXITED: "GREEN_EXITED",
  OFFLINE_ENTERED: "OFFLINE_ENTERED",
  OFFLINE_EXITED: "OFFLINE_EXITED",
  RED_ENTERED: "RED_ENTERED",
  RED_EXITED: "RED_EXITED",
  UNKNOWN_ENTERED: "UNKNOWN_ENTERED",
  UNKNOWN_EXITED: "UNKNOWN_EXITED",
  YELLOW_ENTERED: "YELLOW_ENTERED",
  YELLOW_EXITED: "YELLOW_EXITED",
};

const states = {
  [State.GREEN]: {
    entry: Action.GREEN_ENTERED,
    exit: Action.GREEN_EXITED,
    on: {
      [Event.CHANGE]: State.YELLOW,
      [Event.MAINTENANCE_START]: State.OFFLINE,
      [Event.OUTAGE]: State.UNKNOWN,
    },
  },
  [State.OFFLINE]: {
    entry: Action.OFFLINE_ENTERED,
    exit: Action.OFFLINE_EXITED,
    on: {
      [Event.MAINTENANCE_END]: State.RED,
    },
  },
  [State.RED]: {
    entry: Action.RED_ENTERED,
    exit: Action.RED_EXITED,
    on: {
      [Event.CHANGE]: State.GREEN,
      [Event.MAINTENANCE_START]: State.OFFLINE,
      [Event.OUTAGE]: State.UNKNOWN,
    },
  },
  [State.UNKNOWN]: {
    entry: Action.UNKNOWN_ENTERED,
    exit: Action.UNKNOWN_EXITED,
    on: {
      [Event.MAINTENANCE_START]: State.OFFLINE,
      [Event.RESTORED]: State.RED,
    },
  },
  [State.YELLOW]: {
    entry: Action.YELLOW_ENTERED,
    exit: Action.YELLOW_EXITED,
    on: {
      [Event.CHANGE]: State.RED,
      [Event.MAINTENANCE_START]: State.OFFLINE,
      [Event.OUTAGE]: State.UNKNOWN,
    },
  },
};

const actionsMap = {
  [Action.GREEN_ENTERED]: () => {},
  [Action.GREEN_EXITED]: () => {},
  [Action.OFFLINE_ENTERED]: () => {},
  [Action.OFFLINE_EXITED]: () => {},
  [Action.RED_ENTERED]: () => {},
  [Action.RED_EXITED]: () => {},
  [Action.UNKNOWN_ENTERED]: () => {},
  [Action.UNKNOWN_EXITED]: () => {},
  [Action.YELLOW_ENTERED]: () => {},
  [Action.YELLOW_EXITED]: () => {},
};

const fetchMachine = Machine(
  {
    id: "stopLight",
    initial: State.GREEN,
    states,
  },
  { actions: actionsMap }
);