text: // config.js
  const env = process.env.NODE_ENV; // 'dev' or 'test'
  
  // keyvault.js
  const { DefaultAzureCredential } = require("@azure/identity");
  const { SecretClient } = require("@azure/keyvault-secrets");
  const vaultName = "B2CLabVault";
  const url = `https://${vaultName}.vault.azure.net`;
  const azPodIdentity = new DefaultAzureCredential();
  const keyvaultClient = new SecretClient(url, azPodIdentity);
  exports.keyvaultClient = keyvaultClient;
  
  // b2cConfig.js 
  var b2coptions;
  var b2cDomainHost = "dakirb2c.b2clogin.com";
  var tenantIdGuid = "8736fc97-f3e8-4cb7-a4ac-2a604cbd7c34";
  var policyName = "B2C_1_signupsignin";
  
  function b2coptions() {
      return new Promise(function (resolve, reject) {
          var appid;
          keyvaultClient.getSecret('b2c-clientappid').then(function (secret) {
              appid = secret.value;
              var options = {
                  identityMetadata: "https://" + b2cDomainHost + "/" + tenantIdGuid + "/" + policyName + "/v2.0/.well-known/openid-configuration/",
                  clientID: appid,
                  policyName: policyName,
                  isB2C: true,
                  validateIssuer: false,
                  loggingLevel: 'info',
                  loggingNoPII: false,
                  passReqToCallback: false
              };
              resolve(options);
          }).catch(function (err) {
              return reject(err);
          });
      });
  }
  
  let opts = null;
  function getb2coptions() {
      if (!opts) {
          opts = b2coptions();
      }
      return opts;
  }
  exports.getb2coptions = getb2coptions;
  
  // // db.js
  // const mongoose = require('mongoose');
  // const config = require('./config');
  // const { db: { host, port, name } } = config;
  // const connectionString = `mongodb://${host}:${port}/${name}`;
  // mongoose.connect(connectionString);
  
  // // app.js
  // const express = require('express');
  // const config = require('./config');
  
  // const app = express();
  // app.listen(config.app.port);