Replace the emoji on the Messenger website with the platform’s native ones

messenger-native-emoji.js

// ==UserScript==
// @name         Messenger Native Emoji
// @namespace    http://jedfox.com/
// @version      1.0
// @description  Use native emoji on Messenger
// @author       Jed Fox
// @match        *://*.messenger.com/*
// @grant        GM_addScript
// ==/UserScript==

(function() {
  'use strict';
  const codePointRe = /([0-9a-f]+(?:_[0-9a-f]+)*)\.png$/
  function parse(src) {
    try {
      const [, codes] = codePointRe.exec(src)
      return codes.split("_").map(c => String.fromCodePoint(parseInt(c, 16))).join("")
    } catch (err) {
      return "�"
    }
  }

  function run() {
    document.querySelectorAll('img[src*="emoji.php"]').forEach(image => {
      let emoji = parse(image.src) + '\u{FE0F}'
      let { height } = image.getBoundingClientRect()
      image.outerHTML = `<span ${height ? `style="font-size: ${height}px"` : ''}>${emoji}</span>`
    })
  }

  run()
  let currentUrl = document.location.href
  const observer = new MutationObserver(run);
  const target = document.body;
  const config = { childList: true, subtree: true };
  observer.observe(target, config);
})();