Slack node js code to take a user to a private channel

slack-go-private

function sendGoPrivateMessage(channel, user_id, firstName) {

  let teamId = 'T########';

  let post = 
    {
      channel: channel,
      user: user_id,
      text: 'Hi ' + firstName + ', I can help you book your room. Let\'s work on your new reservation in private.' ,
      attachments: 
      [
        {
          text: 'Use this link if your are '
          + '<https://' + appWorkspace + '/messages/@' + botId + '| using your Browser.>',
          color: '#3AA3E3',
          attachment_type: 'default'
        },
        {
          text: 'Or use the following link if using the Slack App ',
          color: '#3AA3E3',
          attachment_type: 'default'
        },

        {
          text: 'slack://channel?team=' + teamId + '&id=' + botChannel,
          color: '#3AA3E3',
          attachment_type: 'default'
        }
      ],
      response_type: 'ephemeral',
      replace_original: true,          
    }; 

  slackWeb.chat.postMessage(post)
  .then((res) => {
    // 'res' contains information about the posted message
  })
  .catch(console.error);

} // end of sendGoPrivateMessage