RM V2' tracking app

machine.js

const setOnline = assign({
  offline: (context, event) => (context.offline = false),
})
const setOffline = assign({
  offline: (context, event) => (context.offline = true),
})
const setLastUpdate = assign({
  lastUpdate: (context, event) => (context.lastUpdate = Date.now()),
})
const setStatusOk = assign({
  status: (context, event) => (context.status = 'ok'),
})

const startPollingAfterError = (context, event) => {
  // if the first load failed, the poll won't start
  return context.lastUpdate !== 0
}

const wasConnected = (context, event) => {
  return context.lastUpdate !== 0
}
const neverConnected = (context, event) => {
  return context.lastUpdate === 0
}

// Available variables:
// - Machine
// - interpret
// - assign
// - send
// - sendParent
// - spawn
// - raise
// - actions
// - XState (all XState exports)

const fetchMachine = Machine(
  {
    id: 'Current Tracking App',
    initial: 'UIPreloadImage',
    context: {
      offline: false,
      lastUpdate: 0,
      status: 'loading',
    },

    states: {
      UIPreloadImage: {
        // starts loading localizations immediately
        after: { 0: 'loadIntl' },
      },

      // LOADING INTL
      loadIntl: {
        // TODO: speed up machine debugging, then remove it. This transition happens programmatically
        after: { 500: 'order' },

        on: {
          SUCCESS: 'order',
          SUCCESS_EMPTY_MESSAGES: 'order.UIOffline',
          ERROR: 'order.UIOffline',
        },
      },

      // LOADING ORDER
      order: {
        initial: 'loadOrderData',
        states: {
          loadOrderData: {
            on: {
              SUCCESS: {
                target: 'UIShowOrderData',
                actions: ['setOnline', 'setLastUpdate', 'setStatusOk'],
              },
              SUCCESS_WITH_ERROR: { target: 'serverError' },
              ERROR: { target: 'UIOffline', actions: 'setOffline' },
            },
          },
          serverError: {
            on: {
              ORDER_NOT_FOUND: 'UIOrderDeleted',
              TERRITORY_NOT_FOUND: 'UIDeadLink',
              TOKEN_NOT_FOUND: 'UIDeadLink',
              TOKEN_NOT_VALID: 'UIDeadLink',
              TRACKING_BODY_NOT_VALID: 'UIDeadLink',
              DEFAULT: [
                {
                  target: 'UILostConnection',
                  cond: wasConnected,
                },
                {
                  target: 'UIOffline',
                  cond: neverConnected,
                },
              ],
            },
          },

          // UI STATES WITH POLLING
          UIShowOrderData: {
            // TODO: long delay polling
            after: { 1000: 'loadOrderData' },
          },
          UIOffline: {
            type: 'final',
            // start fast polling to exit the offline mode
            after: { 100: { target: 'loadOrderData', cond: startPollingAfterError } },
          },

          // FINAL UI STATES
          UIDeadLink: { type: 'final' },
          UIOrderDeleted: { type: 'final' },
          UILostConnection: { type: 'final' },
        },
        // -------------------
      },
    },
  },
  {
    actions: { setOnline, setOffline, setLastUpdate, setStatusOk },
  }
)