fix: certain characters make Obsidian freeze (#647)

This issue happens when certain characters like "©" are parsed by twemoji.parse() as non-emoji, while isEmoji() passes those. Fix #641

Author: kotaindah55

src/editor/markdown-processors/icon-in-text.ts

@@ -153,15 +153,20 @@ export const processIconInTextMarkdown = (
     }
 
     if (plugin.getSettings().emojiStyle === 'twemoji') {
-      const toReplace = text.splitText(code.index);
-
-      const tagName = toReplace.parentElement?.tagName?.toLowerCase() ?? '';
+  
+      const tagName = text.parentElement?.tagName?.toLowerCase() ?? ''; // "text" has the same parent as "toReplace"
       let fontSize = calculateFontTextSize();
 
       if (isHeader(tagName)) {
         fontSize = calculateHeaderSize(tagName as HTMLHeader);
       }
 
+      // If emojiValue was an unparsed HTML img string, it will be skipped
+      // by the treewalker, as img doesn't have any text node derived from it.
+      // But, unfortunately, when passing certain character like "©" as the
+      // second parameter of emoji.parseEmoji (before it was fixed), it will return
+      // the string itself due to twemoji.parse perceive it as a normal character (non-emoji).
+      // If it is the case, the string will be interpreted as a text node.
       const emojiValue = emoji.parseEmoji(
         plugin.getSettings().emojiStyle,
         code.text,
@@ -171,7 +176,13 @@ export const processIconInTextMarkdown = (
         return;
       }
 
+      // Split the text node only after checking emojiValue.
+      const toReplace = text.splitText(code.index);
       const emojiNode = createSpan();
+      // emojiValue should not be interpreted as a text node or as an element
+      // containing text node, otherwise it will cause endlessly loop
+      // due to TreeWalker considering the first part as its current node,
+      // not the second one (except you add another TreeWalker.nextNode() here).
       emojiNode.innerHTML = emojiValue;
       toReplace.parentElement?.insertBefore(emojiNode, toReplace);
       toReplace.textContent = toReplace.wholeText.substring(code.text.length);

src/emoji.ts

@@ -1879,14 +1879,17 @@ const parseEmoji = (
 ): string | null => {
   switch (style) {
     case 'twemoji':
-      return twemoji.parse(str, {
+      let parsedStr = twemoji.parse(str, {
         folder: 'svg',
         ext: '.svg',
         attributes: () => ({
           width: `${size}px`,
           height: `${size}px`,
         }),
       });
+      // Some characters like "©" are treated as non-emoji, and
+      // isEmoji method passes those. Use below expression to anticipate that.
+      return parsedStr === str ? null : parsedStr;
     case 'native':
       return str;
     default: