If you want to achieve same, what Ran Breuer and Arina Hantsis demonstrate in there video!
you can use these codes...
after reading the documentation, I come up with this solution it took me 5 days to figure out,  anyway I am posting here so everyone can have easy access to codes.  
**AppOwnData Power bi embedded reports ** 
Controller.js 
 const request = require('request');
 const getAccessToken = function () {
return new Promise(function (resolve, reject) {
    const url = 'https://login.microsoftonline.com/common/oauth2/token';
    const username = ''; // Username of PowerBI "pro" account - stored in config
    const password = ''; // Password of PowerBI "pro" account - stored in config
    const clientId = ''; // Applicaton ID of app registered via Azure Active Directory - stored in config
    const headers = {
        'Content-Type': 'application/x-www-form-urlencoded'
    };
    const formData = {
        grant_type: 'password',
        client_id: clientId,
        resource: 'https://analysis.windows.net/powerbi/api',
        scope: 'openid',
        username: username,
        password: password
    };
    request.post({
        url: url,
        form: formData,
        headers: headers
    }, function (err, result, body) {
        if (err) return reject(err);
        const bodyObj = JSON.parse(body);
        resolve(bodyObj.access_token);
    });
   });
  };
  const getReportEmbedToken = function (accessToken, groupId, reportId) {
return new Promise(function (resolve, reject) {
    const url = 'https://api.powerbi.com/v1.0/myorg/groups/' + groupId + '/reports/' + reportId + '/GenerateToken';
    const headers = {
        'Content-Type': 'application/x-www-form-urlencoded',
        'Authorization': 'Bearer ' + accessToken
    };
    const formData = {
        'accessLevel': 'view'
    };
    request.post({
        url: url,
        form: formData,
        headers: headers
    }, function (err, result, body) {
        if (err) return reject(err);
        const bodyObj = JSON.parse(body);
        resolve(bodyObj.token);
    });
});
};
   module.exports = {
embedReport: function (req, res) {
    getAccessToken().then(function (accessToken) {
        getReportEmbedToken(accessToken, req.params.groupId, req.params.reportId).then(function (embedToken) {
            res.render('index', {
                reportId: req.params.dashboardId,
                embedToken,
                embedUrl: 'https://app.powerbi.com/reportEmbed?reportId=' + req.params.reportId + '&groupId=' + req.params.groupId
            });
        }).catch(function (err) {
            res.send(500, err);
        });
    }).catch(function (err) {
        res.send(500, err);
    });
   }
   };
Your router index.js
   const express = require('express'),
   router = express.Router(),
   mainCtrl = require('../controllers/MainController');
  router.get('/report/:groupId/:reportId', mainCtrl.embedReport);
  module.exports = router;
index.ejs or what ever you like 
<!DOCTYPE html>
   <html>
    <head>
  <title>Node.js PowerBI Embed</title>
  <link rel="stylesheet" href="/bootstrap/dist/css/bootstrap.min.css" />
  <style>
    html,
    body {
  height: 100%;
   }
.fill {
  min-height: 100%;
  height: 100%;
  box-sizing: border-box;
}
#reportContainer {
  height: 100%;
  min-height: 100%;
  display: block;
}
</style>
</head>
 <body>
<div class="container-fluid fill">
<div id="reportContainer"></div>
</div>
<script src="/jquery/dist/jquery.min.js"></script>
<script src="/bootstrap/dist/js/bootstrap.min.js"></script>
<script src="/powerbi-client/dist/powerbi.js"></script>
<script>
const models = window['powerbi-client'].models;
const config = {
  type: 'report',
  tokenType: models.TokenType.Embed,
  accessToken: '<%- embedToken %>',
  embedUrl: '<%- embedUrl %>',
  id: '<%- reportId %>'
    };
   // Get a reference to the embedded dashboard HTML element 
   const reportContainer = $('#reportContainer')[0];
  // Embed the dashboard and display it within the div container. 
   powerbi.embed(reportContainer, config);
 </script>
 </body>
</html>
Finally Enjoy 
localhost:4000/report/put your group id here / put you report id here