Example usage of login popup with adal.js

adal-app.js

var authContext = new AuthenticationContext({
  // ...
});

// Our custom asynchronous login function. Uses authContext.config.displayCall
// to show the Azure AD login page in a popup window, then periodically checks
// the popup window for the resulting hash + uses adal.js to handle it.
// For this to work, we need a dummy landing page to use as redirectUri.
// This can be an empty HTML page, but needs to have the same origin as the
// main window.
var dummyAuthPage = 'auth.html';
var getUser = function () {
  return new Promise(function (resolve, reject) {
    // If the user is cached, resolve the promise immediately.
    var user = authContext.getCachedUser();
    if (user) {
      resolve(user);
      return;
    }
		
    // The user was not cached. Open a popup window which
    // performs the OAuth login process, then signals
    // the result.
    authContext.config.displayCall = function (url) {
      authContext.config.displayCall = null;
      var popup = window.open(url, 'auth-popup', 'width=800,height=500');
      var intervalId = window.setInterval(function () {
        try {
          if (popup.location.pathname.indexOf('/' + dummyAuthPage) >= 0) {
            window.clearInterval(intervalId);
            authContext.handleWindowCallback(popup.location.hash);
            popup.close();
            var user = authContext.getCachedUser();
            if (user) {
              resolve(user);
            } else {
              reject(authContext.getLoginError());
            }
          }
        } catch (whatever) {
          if (popup.closed) {
            reject();
          }
        }
      }, 100);
    };

    authContext.config.redirectUri = window.location.href.replace('index.html', '') + dummyAuthPage;
    authContext.login();
  });
};

// Now use getUser() whenever a user token is needed.

anything which says " Promise " is giving error "undefined". e.g. Promise, reject(), resolve() are giving same error.
do i need to include some external java-script library ? can u provide WORKING SAMPLE please ?

i tried the above code on the login page but a popup window is not being displayed

` function Login() {
var dummyAuthPage = 'Login.html';
var getUser = function () {
return new Promise(function (resolve, reject) {
// If the user is cached, resolve the promise immediately.
var user = authContext.getCachedUser();
if (user) {
resolve(user);
return;
}

                authContext.config.displayCall = function (url) {
                    authContext.config.displayCall = null;
                    var popup = window.open(url, 'auth-popup', 'width=800,height=500');
                    var intervalId = window.setInterval(function () {
                        try {
                            if (popup.location.pathname.indexOf('/' + dummyAuthPage) >= 0) {
                                window.clearInterval(intervalId);
                                authContext.handleWindowCallback(popup.location.hash);
                                popup.close();
                                var user = authContext.getCachedUser();
                                if (user) {
                                    resolve(user);
                                } else {
                                    reject(authContext.getLoginError());
                                }
                            }
                        } catch (whatever) {
                            if (popup.closed) {
                                reject();
                            }
                        }
                    }, 100);
                };

                authContext.config.redirectUri = window.location.href.replace('home.html', '') + dummyAuthPage;
                authContext.login();
            });
        };
    }`