auth.js

var request = require('request');
var graph = require('@microsoft/microsoft-graph-client');
var Q = require('q');

// The auth module object.
var auth = {};

auth.getAccessToken = function (tenantId) {
    var deferred = Q.defer();
    var requestParams = {
      grant_type: 'client_credentials',
      client_id: process.env.ClientId,  
      client_secret: process.env.ClientSecret,  
      scope: 'https://graph.microsoft.com/.default'
    };
  
    var url = "https://login.microsoftonline.com/"+ tenantId+"/oauth2/v2.0/token";
    request.post({ url: url, form: requestParams }, function (err, response, body) {
      var parsedBody = JSON.parse(body);
  
      if (err) {
        deferred.reject(err);
      } else if (parsedBody.error) {
        deferred.reject(parsedBody.error_description);
      } else {
        // If successful, return the access token.
        deferred.resolve(parsedBody.access_token);
      }
    });
  
    return deferred.promise;
  };
  
  module.exports = auth;