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

machine.js

const machineConfig = {
  initial: "idle",
  id: "main",
  context: {
    initialTime: 0,
    currentTime: 0,
    notificationTimes: []
  },
  states: {
    idle: {
      on: {
        START: "running",
        RESET: {
          actions: ["reset"]
        },
        SET_TIME: {
          actions: ["setTime"]
        },
        SET_NOTIFICATION_TIMES: {
          internal: false,
          actions: ["setNotifications"]
        }
      }
    },
    running: {
      invoke: [
        { src: "timer", id: "timer" },
        { src: "plantNotifications", id: "plantNotifications" }
      ],
      on: {
        "": {
          target: "idle",
          cond: ({ currentTime }) => currentTime <= 0
        },
        STOP: "idle",
        COUNT_DOWN: {
          actions: ["countDown"]
        }
      }
    }
  }
};

const machineOptions = {
  actions: {
    setNotifications: assign({
      notificationTimes: (context, event) => {
        if (event.type === "SET_NOTIFICATION_TIMES") {
          return event.payload.notificationTimes;
        }
        return context.notificationTimes;
      }
    }),
    setTime: assign({
      initialTime: (context, event) =>
        event.type === "SET_TIME" ? event.payload.time : context.initialTime,
      currentTime: (context, event) =>
        event.type === "SET_TIME" ? event.payload.time : context.currentTime
    }),
    countDown: assign({
      currentTime: context => context.currentTime - secsToMS(1)
    }),
    reset: assign({
      currentTime: context => context.initialTime
    })
  },
  services: {
    timer: () => (cb) => {
      const interval = setInterval(() => {
        cb("COUNT_DOWN");
      }, secsToMS(1));
      return () => {
        clearInterval(interval);
      };
    }
  }
};

const machine = Machine(machineConfig, machineOptions);