Remove use of DOMParser in front-end emoji rewriting code (#20758)

* Add jstest for node ordering in emojify

* Remove use of DOMParser in front-end emoji rewriting code

2 files changed, 21 insertions, 7 deletions

diff --git a/app/javascript/mastodon/features/emoji/__tests__/emoji-test.js b/app/javascript/mastodon/features/emoji/__tests__/emoji-test.js
index 2f19aab7e..72a732e3b 100644
--- a/app/javascript/mastodon/features/emoji/__tests__/emoji-test.js
+++ b/app/javascript/mastodon/features/emoji/__tests__/emoji-test.js
@@ -88,5 +88,10 @@ describe('emoji', () => {
       expect(emojify('💂‍♀️💂‍♂️'))
         .toEqual('<img draggable="false" class="emojione" alt="💂\u200D♀️" title=":female-guard:" src="/emoji/1f482-200d-2640-fe0f_border.svg"><img draggable="false" class="emojione" alt="💂\u200D♂️" title=":male-guard:" src="/emoji/1f482-200d-2642-fe0f_border.svg">');
     });
+
+    it('keeps ordering as expected (issue fixed by PR 20677)', () => {
+      expect(emojify('<p>💕 <a class="hashtag" href="https://example.com/tags/foo" rel="nofollow noopener noreferrer" target="_blank">#<span>foo</span></a> test: foo.</p>'))
+        .toEqual('<p><img draggable="false" class="emojione" alt="💕" title=":two_hearts:" src="/emoji/1f495.svg"> <a class="hashtag" href="https://example.com/tags/foo" rel="nofollow noopener noreferrer" target="_blank">#<span>foo</span></a> test: foo.</p>');
+    });
   });
 });
diff --git a/app/javascript/mastodon/features/emoji/emoji.js b/app/javascript/mastodon/features/emoji/emoji.js
index 52a8458fb..bc3dd8c60 100644
--- a/app/javascript/mastodon/features/emoji/emoji.js
+++ b/app/javascript/mastodon/features/emoji/emoji.js
@@ -19,8 +19,6 @@ const emojiFilename = (filename) => {
   return borderedEmoji.includes(filename) ? (filename + '_border') : filename;
 };
 
-const domParser = new DOMParser();
-
 const emojifyTextNode = (node, customEmojis) => {
   let str = node.textContent;
 
@@ -39,7 +37,7 @@ const emojifyTextNode = (node, customEmojis) => {
       }
     }
 
-    let rend, replacement = '';
+    let rend, replacement = null;
     if (i === str.length) {
       break;
     } else if (str[i] === ':') {
@@ -51,7 +49,14 @@ const emojifyTextNode = (node, customEmojis) => {
         // if you want additional emoji handler, add statements below which set replacement and return true.
         if (shortname in customEmojis) {
           const filename = autoPlayGif ? customEmojis[shortname].url : customEmojis[shortname].static_url;
-          replacement = `<img draggable="false" class="emojione custom-emoji" alt="${shortname}" title="${shortname}" src="${filename}" data-original="${customEmojis[shortname].url}" data-static="${customEmojis[shortname].static_url}" />`;
+          replacement = document.createElement('img');
+          replacement.setAttribute('draggable', false);
+          replacement.setAttribute('class', 'emojione custom-emoji');
+          replacement.setAttribute('alt', shortname);
+          replacement.setAttribute('title', shortname);
+          replacement.setAttribute('src', filename);
+          replacement.setAttribute('data-original', customEmojis[shortname].url);
+          replacement.setAttribute('data-static', customEmojis[shortname].static_url);
           return true;
         }
         return false;
@@ -59,7 +64,12 @@ const emojifyTextNode = (node, customEmojis) => {
     } else { // matched to unicode emoji
       const { filename, shortCode } = unicodeMapping[match];
       const title = shortCode ? `:${shortCode}:` : '';
-      replacement = `<img draggable="false" class="emojione" alt="${match}" title="${title}" src="${assetHost}/emoji/${emojiFilename(filename)}.svg" />`;
+      replacement = document.createElement('img');
+      replacement.setAttribute('draggable', false);
+      replacement.setAttribute('class', 'emojione');
+      replacement.setAttribute('alt', match);
+      replacement.setAttribute('title', title);
+      replacement.setAttribute('src', `${assetHost}/emoji/${emojiFilename(filename)}.svg`);
       rend = i + match.length;
       // If the matched character was followed by VS15 (for selecting text presentation), skip it.
       if (str.codePointAt(rend) === 65038) {
@@ -69,9 +79,8 @@ const emojifyTextNode = (node, customEmojis) => {
 
     fragment.append(document.createTextNode(str.slice(0, i)));
     if (replacement) {
-      fragment.append(domParser.parseFromString(replacement, 'text/html').documentElement.getElementsByTagName('img')[0]);
+      fragment.append(replacement);
     }
-    node.textContent = str.slice(0, i);
     str = str.slice(rend);
   }