Function checkMention

packages/shared/src/hooks/input/useMarkdownInput.ts:368–406

(position?: number[])

   * @see https://linear.app/dailydotdev/issue/ENG-228
   */
  const checkMention = (position?: number[]) => {
    const current = [textarea.selectionStart, textarea.selectionEnd];
    const selection = position ?? current;
    const [word] = getCloseWord(textarea, selection);
    const mention = word.substring(1);
    const isValid =
      word.charAt(0) === '@' &&
      (mention.length === 0 || handleRegex.test(mention));

    if (!isValid) {
      return updateQuery(undefined);
    }

    // Skip mention detection if @ is inside a markdown link
    if (isSelectionInMarkdownLink(textarea, selection[0], selection[1])) {
      return updateQuery(undefined);
    }

    // Skip mention detection if @ is part of a URL
    // Check if the word containing @ is a URL (with or without protocol)
    // This regex matches:
    // - URLs starting with www.
    // - URLs with http:// or https://
    // - Domain-like patterns (e.g., example.com, sub.domain.com)
    const looksLikeUrl =
      isValidHttpUrl(word) ||
      word.startsWith('www.') ||
      /^[a-zA-Z0-9-]+\.[a-zA-Z0-9-]+/i.test(word);

    if (looksLikeUrl) {
      return updateQuery(undefined);
    }

    if (isNullOrUndefined(query)) {
      return updateQuery(mention ?? '');
    }

    return updateQuery(mention);
  };

  const checkEmoji = (position?: number[]) => {
    const current = [textarea.selectionStart, textarea.selectionEnd];