A little chunk of code to cheat in a counting Whatsapp group

whatsapp-counting-autoresponder.js

// config
var only_respond = true; // if false, responds to own messages as well

// state
var lastno = 34350; // the last known posted number
var mine = true; // was this last number my own post?


// The complication here, is that
//  Whatsapp removes/replaces elements on-the-fly
//  sometimes; e.g. when messages have been deleted, etc.
// And of course, number posts are intersperced with
//  regular conversation.
// The most robust method to check for new numbers, then,
//  is to just check a reasonable backlog of messages for
//  new numbers, and to this often enough.
function get_most_recent () {
  // var wrap = document.querySelector('._9tCEa');
  var wrap = document.querySelector('#main header').nextSibling.lastChild.lastChild.lastChild;
  for (var i = Math.max(0, wrap.children.length - 20); i < wrap.children.length; i++) {
    var msg = wrap.children[i];
    var el = msg.querySelector('._3zb-j.ZhF0n');
    if (el) {
      var text = el.innerText;
      // Check for correct number formatting
      //  so as not to get tricked again. (Stijn !)
      var m = text.match(/^([0-9]\.|[0-9]{2}\.)([0-9]{3}\.)*[0-9]{3}$/);
      if (m) {
        var n = parseInt(text.replace(/\./g, ''));
        if (n == lastno + 1) {
          lastno = n;
          maybe_congratulate(lastno, true);
          mine = !!msg.querySelector('.message-out');
          console.log(`Found: ${lastno} ${mine ? ' (mine)' : ''}`);
        }
      }
    }
  }
}

// Enter number, and simulate an "input" event to
//  get Whatsapp to show the "post message" icon
function enter (str) {
  var input = document.querySelector('[contenteditable]');
  input.innerText = str;
  var e = new Event('input', { bubbles: true, cancelable: true });
  input.dispatchEvent(e);
}

// Simulate button press
function post () {
  var button = document.querySelector('button [data-icon="send"]').parentElement;
  var e = document.createEvent('MouseEvent');
  e.initMouseEvent("click", true, true, window, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, null);
  button.dispatchEvent(e);
}


var waiting_time = () => 2 + 8 * Math.random();

/*
function waiting_time (n1) {
  if (n1 % 100 == 0) {
    console.log(` >> multiple of 100 ! (I'll respond immediately)`);
    return 0;
  }

  if ((n1+'') == (n1+'').split('').reverse().join('')) {
    console.log(` >> palindrome ! (I'll respond immediately)`);
    return 0;
  }

  var rand = Math.random();

  if (rand <= .05) {
    console.log(` >> very long wait (5 min, 5% chance)`);
    return 5 * 60;
  }

  if (rand <= .1) {
    console.log(` >> long wait (1 min, 5% chance)`);
    return 60;
  }

  if (rand <= .8) {
    console.log(` >> regular wait (±9s, 70% chance)`);
    return 7 + 4 * Math.random();
  }

  console.log(` >> short wait (±2s, 20% chance)`);
  return 1 + 2 * Math.random();
}
*/


var r;

function maybe_respond () {
  var n = lastno;

  console.log(`I may respond to: ${n}`);
  var formatted = ((n+1)+'').split('').reduceRight((str, c) => c+(str.replace(/\./, '').length % 3 == 0 ? '.' : '')+str);
  var wait = waiting_time(n+1);

  console.log(`=> Waiting ${wait}s ...`);
  r = {
    responding_to: n,
    h: setTimeout(() => {
      if (n != lastno) {
        console.log(`=> No longer timely! ${n} != ${lastno} (current)`);
      } else {
        enter(formatted);
        post();

        maybe_congratulate(lastno = n+1, false);
        mine = true;
        
        console.log(`=> Just responded ${formatted}`);
      }
    }, wait*1000),
  };
}


function maybe_congratulate (n, other) {
  if (n % 1000 == 0) {
    enter(`🦑🦐🦀 Een duizendtal! ${other ? 'Gefeliciteerd!' : ''}`);
    post();
    return;
  }

  if (n % 100 == 0) {
    enter(`☘🍀 Een honderdtal! ${other ? 'Gefeliciteerd!' : ''}`);
    post();
    return;
  }

  if ((n+'') == (n+'').split('').reverse().join('')) {
    enter(`🐛🦋 Een palindroom! ${other ? 'Gefeliciteerd!' : ''}`);
    post();
    return;
  }
}



function loop () {
  get_most_recent();

  // spin off a helper function that may respond to this number (after some artifical delay)
  if (!mine) {
    if (!r || r.responding_to != lastno) {
      if (r) clearTimeout(r.h);
      maybe_respond();
    }
  }

  // ...but keep this loop running fast in order to keep track of the counting
  requestAnimationFrame(loop);
};

/*
  USAGE:
  1. open web whatsapp and go to the group in question (don't navigate afterwards, because then the `wrap` element changes)
  2. copy code into Firefox' (Chrome's?) devtools
  3. set `lastno` and `mine` accordingly
  4. call `loop()`
  5. sit back and enjoy :)
*/