Automation for sending Invites on Slack. Based on Google Forms and Google script. For more context read https://levels.io/slack-typeform-auto-invite-sign-ups/

SlackAutoInvite.js

/* 

To automate your slack instance invites,

1. Create a google form with two text fields:
"Your email"
"Who invite you"

2. You will get a google table with responses and 3 fields:
1) "Timestamp"	
2) "Your email"
3) "Who invite you"

3. On the resultant google sheet, Go to "Tools" -> "Script Editor"

4. Copy-paste this script.

5. Populate secrets strings (see below) by your very own values.

6. Click "Run" -> "Initialize"

Congratulations, you are successfully rool-out invite automation!

To get Slack Auth token:
-----------------------

1. Go to https://api.slack.com/web

2. At the bottom of them, you will see the section "Authentication"

3. Click the 'Generate token' button against the team you want to automate the notifications. 
The token generated appears right there.
*/

// secrets
var SlackName = 'n***'; // id of your slack
var SlackToken = 'xoxs-359****'; // Slack auth token
var ccEmail = 'x****'; // your email, if you want to get email notification (otherwise comment out SendEmail call)
// end secrets

function Initialize() {
 
  var triggers = ScriptApp.getProjectTriggers();
 
  for (var i in triggers) {
    ScriptApp.deleteTrigger(triggers[i]);
  }
 
  ScriptApp.newTrigger("onFormSubmitEx")
    .forSpreadsheet(SpreadsheetApp.getActiveSpreadsheet())
    .onFormSubmit()
    .create();
 
}

function post(url, payload) {
  
  var options =
      {
        "method"  : "POST",
        "payload" : payload,   
        "followRedirects" : true,
        "muteHttpExceptions": true
      };
  
  var result = UrlFetchApp.fetch(url, options);
  return result.getContentText();
}

// send email to your ccEmail with sign-up info
function SendMail(newEmail, whoInvite, curlStatus) {
 
  try {
    // This will show up as the sender's name
    sendername = "Slack auto-invite";
 
    // Optional but change the following variable
    // to have a custom subject for Google Docs emails
    subject = "New user signed up";
 
    // This is the body of the auto-reply
    message = "New user <b>" +  newEmail + "</b> signed up<br><br>";
    message += 'Invited by  :: ' + whoInvite + "<br>";
    message += 'Curl status :: ' + curlStatus + "<br>";
 
    textbody = message.replace("<br>", "\n");
 
    GmailApp.sendEmail(ccEmail, subject, textbody, {
      cc: ccEmail,
      name: sendername,
      htmlBody: message
    });
 
  } catch (e) {
    Logger.log(e.toString());
  }
 
}

function onFormSubmitEx(e) {

  var timestamp = e.values[0];
  var toAddress = e.values[1];
  var whoInvite = e.values[2];
  var slackInviteUrl = 'https://' + SlackName + '.slack.com/api/users.admin.invite';
  
  var curlStatus = post(slackInviteUrl, {
    token: SlackToken,
    email: toAddress
  });
  SendMail(toAddress, whoInvite, curlStatus);
}