Invite all users to slack channel

invite-all-users-to-slack-channel.js

var i = 1;                     

function inviteAllUsers() {           
  setTimeout(function () {    
      setTimeout(function() {
        $('#channel_actions_toggle').click();
      },100)
      setTimeout(function() {
        $('#channel_invite_item').click();
      },200)
      setTimeout(function() {
        if ($('.lfs_item').length == 0) {
          i = 0;
        }
        $('.lfs_item').each(function(i, obj) {
            this.click();
        });
      },300)
      setTimeout(function() {
        $('.invite_go').click()
      },400)                   
      if (i == 1) {            
         inviteAllUsers();             
      }                        
   }, 4000)
}

inviteAllUsers();                      

Update - Oct 2020. If you are looking for a no-code solution, you can use Channel Tools app to invite all users to a Slack channel.