What's App Automated "New Year Wish" Script

WhatsAppAutomationScript.js

let listOfRecentContacts = document.getElementsByClassName("_3j7s9");
console.log("listOfRecentContacts.length = " + listOfRecentContacts.length);
var eventToSwitchMessageBox = new MouseEvent('mousedown', {
    bubbles: true,
});
let count =1;
let openMessageBox = setInterval(function(){
    // if(count>listOfRecentContacts.length) {
    if(count>5) {
        console.log("Clearing interval with clearInterval...");
        clearInterval(openMessageBox);
    }
    listOfRecentContacts[count].dispatchEvent(eventToSwitchMessageBox);
    console.log("Opening message box of " + listOfRecentContacts[count].getElementsByClassName("_1wjpf")[0].title + " -> " + count);

    // let textToSend = "Hello " + listOfRecentContacts[count-1].getElementsByClassName("_1wjpf")[0].title + ". I hope you are doing great. This is an autogenerated message from Bisso. Please Ignore. Do not reply.";
    let textToSend = "Hello. Wish you a very happy new year from Bisso. PS: Ignore this message I am testing out a program.";

    let textbox = document.querySelector('div._2S1VP');
    let sendMessageEvent = new InputEvent('input', {
        bubbles: true
    });
    textbox.textContent =textToSend;
    textbox.dispatchEvent(sendMessageEvent);
    document.querySelector("button._35EW6").click();  
    count++;
 }, 3000);

Hey Bisso, I've tried the code but the message was sent only to 21 people while my contact list has about 600 people. What do you think the issue here could be?

Yeah so the script uses DOM manipulation.
That means for now it cannot message all 600 people but can message only the most recently contacted ones.
You can modify the script to add a scroll function that would keep on adding more and more contacts one by one to the DOM.