Facebook, scrape conversation messages

index.js

;(async () => {
  console.info('Type stop() to stop.')
  const sleep = (ms) => new Promise((res) => setTimeout(res, ms));

  const msgSelector = ".j83agx80.jwdofwj8.pby63qed";
  const msgTextSelector = ".oo9gr5id[dir=auto]";
  const msgAuthorSelector = ".pfnyh3mw.r9r71o1u.m9osqain.fsrhnwul.dkr8dfph";
  const scrollableSelector =
    ".buofh1pr.j83agx80.eg9m0zos.ni8dbmo4.cbu4d94t.gok29vw1";
  const msgContainerSelector = '[aria-label=Messages]';

  const scrollElem = document.querySelector(scrollableSelector);
  const msgContainer = scrollElem.querySelector(msgContainerSelector);

  let resumeFlag = 1;

  window.messages = [];
  window.stop = () => {
    console.info('Stopped');
    resumeFlag = 0;
    scrollElem.querySelectorAll(msgSelector).forEach((group) => {
      const author = group.querySelector(msgAuthorSelector).innerText;
      const content = group.querySelector(msgTextSelector)?.innerText;
      window.messages.push({ author, content });
    });

    const btn = document.createElement('button');
    const serialized = JSON.stringify(messages);
    btn.onclick = () => navigator.clipboard.writeText(serialized);
    btn.innerHTML = "COPY RECORDED MESSAGES TO THE CLIPBOARD";
    btn.style = "position: fixed; z-index: 99999; top: 0; left: 0; right: 0; height: 100px;"
    document.body.prepend(btn);
    console.log(serialized);
    console.log('Press the button to copy messages to the clipboard.')
  };

  while (resumeFlag) {
    scrollElem.scrollTop = 1000;
    await sleep(1000);
    scrollElem.scrollTop = 0;
    await sleep(1000);
    console.info(`Approx messages in view: ${msgContainer.childElementCount}`);
  }
})();