slack-to-meet.user.js

// ==UserScript==
// @name         Slack To Meet
// @version      0.2
// @description  Add a button to Slack to create a Google Meet and send the link
// @author       blastrock
// @match        https://app.slack.com/*
// @require      https://raw.githubusercontent.com/uzairfarooq/arrive/master/minified/arrive.min.js
// @grant        none
// ==/UserScript==

(function() {
    'use strict';

    const arriveOpt = {
        existing: true,
    };

    async function sendMeetImpl(messageText, sendButton) {
        const randId = Math.random().toString().substring(2);
        messageText.innerHTML = `https://g.co/meet/${randId}`;
        await new Promise(r => setTimeout(r, 200));
        sendButton.click();
    }

    async function sendMeet() {
        const sendButton = document.querySelector('button[data-qa="texty_send_button"]');
        const messageText = document.querySelector('div[data-qa="message_input"] div p');
        sendMeetImpl(messageText, sendButton);
    }
  
    async function sendMeetThread() {
        const sendButton = document.querySelector('div.p-threads_flexpane div[data-qa="reply_container"] button[data-qa="texty_send_button"]');
        const messageText = document.querySelector('div.p-threads_flexpane div[data-qa="message_input"] div p');
        sendMeetImpl(messageText, sendButton);
    }

    document.arrive('div.p-ia__view_header', arriveOpt, function () {
        const meetButton = document.createElement("button");
        meetButton.innerHTML = "Create Meet";
        meetButton.setAttribute("class", "c-button-unstyled");
        meetButton.setAttribute("data-qa", "slack-meet");
        meetButton.onclick = sendMeet;

        const upBar = this;
        const config = { childList: true };
        const callback = () => {
            if (upBar.querySelector('button[data-qa="channel-details"]'))
            {
                if (!upBar.querySelector('button[data-qa="slack-meet"]'))
                    upBar.appendChild(meetButton);
            } else {
                upBar.removeChild(meetButton);
            }
        };

        const observer = new MutationObserver(callback);
        observer.observe(upBar, config);

        callback();
    });
  
    document.arrive('div.p-flexpane_header__primary', arriveOpt, function () {
        const upBar = this;
        const meetButton = document.createElement("button");
        meetButton.innerHTML = "Create Meet";
        meetButton.setAttribute("class", "c-button-unstyled");
        meetButton.onclick = sendMeetThread;
        const closeButton = upBar.querySelector('button[data-qa="close_flexpane"]');
        upBar.insertBefore(meetButton, closeButton);
    });
})();