title: define is not defined in nodejs typescript app
body: <p>I am working on nodejs app in typescript in which i have wrote  a file server.js  as fallow  :</p>
  
  <pre><code>import express = require('express');
  import mongoose = require('mongoose');
  
  
  let app=express();
  app.set('port', process.env.PORT || 3000); // Set port to 3000 or the provided PORT variable
  
  
  /**
   * Start app 
   */
  app.listen(app.get('port'), function() {
    console.log(`App listening on port ${app.get('port')}!`);
  });
  </code></pre>
  
  <p>i have use the gulp to traspile it which  generate js file as</p>
  
  <pre><code>define(["require", "exports", 'express'], function (require, exports, express) {
      var app = express();
      app.set('port', process.env.PORT || 3000); // Set port to 3000 or the provided PORT variable
      /**
       * Start app
       */
      app.listen(app.get('port'), function () {
          console.log("App listening on port " + app.get('port') + "!");
      });
  });
  
  //# sourceMappingURL=../map/server.js.map
  </code></pre>
  
  <p>but when i run this file am getting error define is not define. </p>
  
  <p>Please correct me if i am doing any mistake.</p>
  
  <p><a href="https://i.stack.imgur.com/krChZ.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/krChZ.jpg" alt="enter image description here"></a></p>