const options: NvRFBDefaults = {
          target: this.vncContainer.nativeElement,
          onDisconnected: (rfb: RFB, reason) => {
            console.log('VNC Disconnect');
          },
          onPasswordRequired: (rfb: RFB, ) => {
            console.log('VNC Credentials Required');
          }
        };

        this.connection = new RFB(options);

ERROR Error: Must specify URL
    at new RFB (VM85 iframe.bundle.js:211765)

  // Creating a new RFB object will start a new connection
        rfb = new RFB(document.getElementById('screen'), url,
                      { credentials: { password: password } });
        // Add listeners to important events from the RFB module
        rfb.addEventListener("connect",  connectedToServer);
        rfb.addEventListener("disconnect", disconnectedFromServer);
        rfb.addEventListener("credentialsrequired", credentialsAreRequired);
        rfb.addEventListener("desktopname", updateDesktopName);
        // Set parameters that can be changed on an active connection
        rfb.viewOnly = readQueryVariable('view_only', false);
        rfb.scaleViewport = readQueryVariable('scale', false);

// @ts-ignore
        this.connection = new RFB(
          this.vncContainer.nativeElement,
          connectionInfo.fullWebsocketUrl
        );

        this.connection.scaleViewport = true;
        this.connection.focusOnClick = true;
        this.connection.clipViewport = true;
        this.connection.resizeSession = true;
        this.connection.viewOnly = false;

        this.connection.addEventlistener('disconnect', () => {
          console.log('VNC Disconnect');
        });

        this.connection.addEventListener('securityfailure', () => {
          console.log('VNC Security Failure');
        });

        this.connection.addEventListener('credentialsrequired', () => {
          console.log('VNC Credentials Required');
        });