Function not found NodeJS?

Question

So I have started to learn NodeJS again. I wanted to use a cool tutorial I found. However it gives an error?

in app.js I have

require("dotenv").config();
const express = require("express");
const { loadClient, listEvents, createEvent } = require("./apiClient");

const app = express();
const port = 3000;

loadClient();

/* GET home page. */
router.get('/', function(req, res, next) {
  res.render('index', { title: 'Express' });
});

// Make a GET request to return a list of events in JSON
app.get("/lijst", function(req, res) {
  listEvents((events) => res.json(events));
});

// Make a POST request to create a new event in the calendar
app.post("/create", (req, res) => {
  createEvent((event) => {
    res.json(event);
  });
});

app.listen(port, () =>
  console.log(`Example app listening at http://localhost:${port}`)
);
module.exports = router;

apiCLient:

const { google } = require("googleapis");

const token = process.env.REFRESH_TOKEN;
const client_id = process.env.CLIENT_ID;
const client_secret = process.env.CLIENT_SECRET;
const redirect_url = "localhost:3000";

const loadClient = () => {
  const auth = new google.auth.OAuth2(client_id, client_secret, redirect_url);

  auth.setCredentials({ refresh_token: token });
  google.options({ auth });
};

const makeApiCall = () => {
  const calendar = google.calendar({ version: "v3" });
};

const getEvents = (instance, event, callback) => {
    const calendarId = "primary";
    const query = {
      resource: {
        timeMin: event.start.dateTime,
        timeMax: event.end.dateTime,
        items: [{ id: calendarId }],
      },
    };
  
    // Return a list of events
    instance.freebusy
      .query(query)
      .then((response) => {
        const { data } = response;
        const { calendars } = data;
        const { busy } = calendars[calendarId];
  
        callback(null, busy);
      })
      .catch((err) => {
        callback(err, null);
      });
  };

  const listEvents = (callback) => {
  const calendar = google.calendar({ version: "v3" });
  calendar.events.list(
    {
      calendarId: "primary",
      timeMin: new Date().toISOString(), // Look for events from now onwards
      maxResults: 10, // Limit to 10 events
      singleEvents: true,
      orderBy: "startTime",
    },
    (err, res) => {
      if (err) return console.log("The API returned an error: " + err);

      const events = res.data.items;
      callback(events);
    }
  );
};
const createEvent = (callback) => {
    // Instance of calendar
    const calendar = google.calendar({ version: "v3" });
  
    // Start date set to next day 3PM
    const startTime = new Date();
    startTime.setDate(startTime.getDate() + 1);
    startTime.setHours(15, 0, 0, 0);
  
    // End time set 1 hour after start time
    const endTime = new Date(startTime.getTime());
    endTime.setMinutes(startTime.getMinutes() + 60);
  
    const newEvent = {
      calendarId: "primary",
      resource: {
        start: {
          dateTime: startTime.toISOString(),
        },
        end: {
          dateTime: endTime.toISOString(),
        },
      },
    };
  
    calendar.events.insert(newEvent, (err, event) => {
      if (err) console.log(err);
      callback(event.data.htmlLink);
    });
  };

ERROR LOG/

C:\Users\gebruiker\Desktop\hello\myExpressApp\routes\index.js:9
loadClient();
^

TypeError: loadClient is not a function
    at Object.<anonymous> (C:\Users\gebruiker\Desktop\hello\myExpressApp\routes\index.js:9:1)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
    at Module.load (internal/modules/cjs/loader.js:928:32)
    at Function.Module._load (internal/modules/cjs/loader.js:769:14)
    at Module.require (internal/modules/cjs/loader.js:952:19)
    at require (internal/modules/cjs/helpers.js:88:18)
    at Object.<anonymous> (C:\Users\gebruiker\Desktop\hello\myExpressApp\app.js:7:19)
    at Module._compile (internal/modules/cjs/loader.js:1063:30)
    at Object.Module._extensions..js (internal/modules/cjs/loader.js:1092:10)
  

Answer 1

you should exports functions, you can do like this, add this lines add the end of apiCLient:

  exports.loadClient = loadClient
  exports.makeApiCall = makeApiCall
  exports.getEvents = getEvents
  exports.listEvents = listEvents
  exports.createEvent = createEvent

or

  module.exports ={
    loadClient : loadClient,
    makeApiCall : makeApiCall,
    getEvents : getEvents,
    listEvents : listEvents,
    createEvent : createEvent
  }