display ROC flag

flag.js

// ==UserScript==
// @name         mac-ROC-flag
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Replace ROC flag unicode to images in Apple devices
// @author       tizee
// @homepage     https://github.com/twitter/twemoji/tree/master
// @icon         https://cdn.jsdelivr.net/gh/twitter/twemoji@latest/assets/72x72/1f1f9-1f1fc.png
// @grant        GM_addStyle
// @match        *://*/*
// @require      https://unpkg.com/twemoji@latest/dist/twemoji.min.js
// ==/UserScript==

(function() {
    'use strict';
    let _ = document;

    GM_addStyle(`img.emoji {
   height: 1em;
   width: 1em;
   margin: 0 .05em 0 .1em;
   vertical-align: -0.1em;
   }`);

   function replaceROCFlag(node) {
    // ROC flag = \uD83C\uDDF9\uD83C\uDDFC
    // T: \uD83C\uDDF9
    // W: \uD83C\uDDFC
    let flag =/\uD83C\uDDF9\uD83C\uDDFC/g;
    let match = undefined;
    if (!node.nodeValue || !(match = flag.exec(node.nodeValue))) {
        return false;
    }

    // modify the text node's container
    let res = twemoji.parse(node.parentNode,{
       folder: 'svg',
       ext: '.svg',
       // https://github.com/twitter/twemoji/issues/580
       base: 'https://cdn.jsdelivr.net/gh/twitter/twemoji@latest/assets/'
     });
     console.debug('Replace ROC flag:', node, res);
     return true;
   }

   // Watch newly added DOM nodes
   function mutationHandler(mutationList) {
    mutationList.forEach(function(mutationRecord) {
        mutationRecord.addedNodes.forEach(function(node) {
            scanTextNodes(node);
        });
    });
   }

    // dfs
    function scanTextNodes(node) {
    // The node could have been detached from the DOM tree
    if (!node.parentNode || !_.body.contains(node)) {
        return;
    }

    // Ignore text boxes and echoes
    let excludeTags = {ruby: true, script: true, select: true, textarea: true};

    switch (node.nodeType) {
    case Node.ELEMENT_NODE:
        if (node.tagName.toLowerCase() in excludeTags || node.isContentEditable) {
            return;
        }
        return node.childNodes.forEach(scanTextNodes);

     case Node.TEXT_NODE:
        return replaceROCFlag(node);
     }
   }

    // this script does not support mobile devices
    if (/iPhone|iPad|iPod|Android/i.test(navigator.userAgent)) {
       return;
    }

    const pl = window.navigator.platform.toLowerCase();
    const platform = pl.indexOf("mac") >= 0 ? "m" : pl.indexOf("win") >= 0 ? "w" : pl.indexOf("linux") >= 0 ? "l" : pl.indexOf("x11") >= 0 ? "l" : undefined;

    // only apple devices need this script
    if (platform!="m") {
      return;
    }

    let observer = new MutationObserver(mutationHandler);
    observer.observe(_.body, {childList: true, subtree: true});
    scanTextNodes(_.body);
})();