Javscript to invite all slack users to a channel.

README

1. Open slack in a browser
2. Go to the channel you want to invite everyone to
3. Using Command/Control and the '-' key, make the page small
4. Open the Javascript console
5. Copy into the console the contents of inviteusers.js
6. Hit enter and watch it invite the users.
7. You might have to run it a few times if you have a lot of users and it doesnt add everyone at first
8. Took 4 times to invite 3,000 people to a channel on my slack 

inviteusers.js

var foundAny=false;
function selectAllByLetter(remainingLetters) {
  console.log(remainingLetters)
  var letter = remainingLetters.pop();
  $("#channel_invite_filter").val(letter).trigger("input");
  setTimeout(function() {
    $(".channel_invite_member:not(hidden)").each(function(i, obj) {
        foundAny=true;
        this.click();
    });
    if (remainingLetters.length) {
      selectAllByLetter(remainingLetters);
    } else {
      setTimeout(function() {
        console.log("Inviting them all!")
        $('.invite_go').click()
      },400)     
    }
  },300);
}

function inviteAllUsers() {      
  foundAny=false;     
  setTimeout(function () {    
      setTimeout(function() {
        $('#channel_actions_toggle').click();
      },100)
      setTimeout(function() {
        $('#channel_invite_item').click();
      },200)
      //Enter each letter to trigger searches
      var remainingLetters = ["a","b","c","d","e","f","g","h","i","j","v","k","l","m","n","o","p","q","r","s","t","u","v","w","x","y","z"];
      selectAllByLetter(remainingLetters);
      if (foundAny) {
        inviteAllUsers();
      }
   }, 4000);
}

inviteAllUsers();