text: var fs = require('fs');
  var readline = require('readline');
  var google = require('googleapis');
  var googleAuth = require('google-auth-library');
  
  // If modifying these scopes, delete your previously saved credentials
  // at ~/.credentials/sheets.googleapis.com-nodejs-quickstart.json
  var SCOPES = ['https://www.googleapis.com/auth/spreadsheets'];
  var TOKEN_DIR = (process.env.HOME || process.env.HOMEPATH ||
      process.env.USERPROFILE) + '/.credentials/';
      console.log(TOKEN_DIR)
  var TOKEN_PATH = TOKEN_DIR + 'sheets.googleapis.com-nodejs-quickstart.json';
  
  // Load client secrets from a local file.
  
  var dataArray= new Array();
  module.exports.updateGoogleSheet= function(data){
      dataArray=data
  
      fs.readFile('client_secret.json', function processClientSecrets(err, content) {
        if (err) {
          console.log('Error loading client secret file: ' + err);
          return;
        }
        // Authorize a client with the loaded credentials, then call the
        // Google Sheets API.
       // authorize(JSON.parse(content), listMajors);
  
          authorize(JSON.parse(content), updateSheet);
      });
  
  }
  
  
  
  /**
   * Create an OAuth2 client with the given credentials, and then execute the
   * given callback function.
   *
   * @param {Object} credentials The authorization client credentials.
   * @param {function} callback The callback to call with the authorized client.
   */
  function authorize(credentials, callback) {
    var clientSecret = credentials.installed.client_secret;
    var clientId = credentials.installed.client_id;
    var redirectUrl = credentials.installed.redirect_uris[0];
    var auth = new googleAuth();
    var oauth2Client = new auth.OAuth2(clientId, clientSecret, redirectUrl);
  
    // Check if we have previously stored a token.
    fs.readFile(TOKEN_PATH, function(err, token) {
      if (err) {
        getNewToken(oauth2Client, callback);
      } else {
        oauth2Client.credentials = JSON.parse(token);
        callback(oauth2Client);
      }
    });
  }
  
  /**
   * Get and store new token after prompting for user authorization, and then
   * execute the given callback with the authorized OAuth2 client.
   *
   * @param {google.auth.OAuth2} oauth2Client The OAuth2 client to get token for.
   * @param {getEventsCallback} callback The callback to call with the authorized
   *     client.
   */
  function getNewToken(oauth2Client, callback) {
    var authUrl = oauth2Client.generateAuthUrl({
      access_type: 'offline',
      scope: SCOPES
    });
    console.log('Authorize this app by visiting this url: ', authUrl);
    var rl = readline.createInterface({
      input: process.stdin,
      output: process.stdout
    });
    rl.question('Enter the code from that page here: ', function(code) {
      rl.close();
      oauth2Client.getToken(code, function(err, token) {
        if (err) {
          console.log('Error while trying to retrieve access token', err);
          return;
        }
        oauth2Client.credentials = token;
        storeToken(token);
        callback(oauth2Client);
      });
    });
  }
  
  /**
   * Store token to disk be used in later program executions.
   *
   * @param {Object} token The token to store to disk.
   */
  function storeToken(token) {
    try {
      fs.mkdirSync(TOKEN_DIR);
    } catch (err) {
      if (err.code != 'EEXIST') {
        throw err;
      }
    }
    fs.writeFile(TOKEN_PATH, JSON.stringify(token));
    console.log('Token stored to ' + TOKEN_PATH);
  }
  
  /
  
  function updateSheet(auth){
  
   var sheets = google.sheets('v4');
    sheets.spreadsheets.values.append({
      auth: auth,
      spreadsheetId: 'YOUR SPREADSHEET ID', // spread sheet ID need to be proided by user
      range: 'Sheet1!A2:B', //Change Sheet1 if your worksheet's name is something else
      valueInputOption: "USER_ENTERED",
      resource: {
        values: [dataArray ]
      }
    }, (err, response) => {
      if (err) {
        console.log('The API returned an error: ' + err);
        return;
      } else {
          console.log("Appended");
      }
    });
  }
  
  