refactor: extract specialCharsRegex to shared utilities and add JSDoc comments

- Extract duplicated specialCharsRegex constant to packages/shared/src/lib/strings.ts
- Update imports in useEmojiAutocomplete.ts and useMarkdownInput.ts to use shared constant
- Add JSDoc comments to markdownToHtmlBasic and htmlToMarkdownBasic functions
- Fix prettier formatting in RichTextInput.tsx

Co-authored-by: Chris Bongers <rebelchris@users.noreply.github.com>

Author: github-actions[bot]

packages/shared/src/components/fields/RichTextEditor/useEmojiAutocomplete.ts

@@ -1,11 +1,10 @@
 import { useCallback, useEffect, useMemo, useRef, useState } from 'react';
 import type { Editor } from '@tiptap/react';
 import { search as emojiSearch } from 'node-emoji';
+import { specialCharsRegex } from '../../../lib/strings';
 
 type EditorRange = { from: number; to: number } | null;
 
-const specialCharsRegex = new RegExp(/[^A-Za-z0-9_.]/);
-
 interface UseEmojiAutocompleteProps {
   enabled: boolean;
   onOffsetUpdate: (editor: Editor) => void;

packages/shared/src/components/fields/RichTextInput.tsx

@@ -664,9 +664,7 @@ function RichTextInput(
                       .insertContent({
                         type: 'text',
                         text: linkText,
-                        marks: [
-                          { type: 'link', attrs: { href: url } },
-                        ],
+                        marks: [{ type: 'link', attrs: { href: url } }],
                       })
                       .run();
                   }}

packages/shared/src/hooks/input/useMarkdownInput.ts

@@ -49,6 +49,7 @@ import {
 } from '../../graphql/posts';
 import { generateStorageKey, StorageTopic } from '../../lib/storage';
 import { storageWrapper } from '../../lib/storageWrapper';
+import { specialCharsRegex } from '../../lib/strings';
 
 export enum MarkdownCommand {
   Upload = 'upload',
@@ -108,8 +109,6 @@ export const defaultMarkdownCommands = {
   gif: true,
 };
 
-const specialCharsRegex = new RegExp(/[^A-Za-z0-9_.]/);
-
 export const useMarkdownInput = ({
   textareaRef,
   postId,

packages/shared/src/lib/markdownConversion.ts

@@ -29,6 +29,18 @@ const inlineMarkdownToHtml = (value: string): string => {
   return result;
 };
 
+/**
+ * Converts markdown to HTML using basic markdown syntax.
+ * Supports headings, lists (ordered/unordered), code blocks, inline code,
+ * bold, italic, links, and images.
+ *
+ * @param markdown - The markdown string to convert
+ * @returns HTML string representation of the markdown
+ *
+ * @example
+ * markdownToHtmlBasic('**bold** and _italic_')
+ * // Returns: '<p><strong>bold</strong> and <em>italic</em></p>'
+ */
 export const markdownToHtmlBasic = (markdown: string): string => {
   if (!markdown) {
     return '';
@@ -191,6 +203,18 @@ const serializeList = (node: Element, ordered: boolean): string => {
     .join('\n');
 };
 
+/**
+ * Converts HTML to markdown using basic markdown syntax.
+ * Supports headings, lists (ordered/unordered), code blocks, inline code,
+ * bold, italic, links, and images.
+ *
+ * @param html - The HTML string to convert
+ * @returns Markdown string representation of the HTML
+ *
+ * @example
+ * htmlToMarkdownBasic('<p><strong>bold</strong> and <em>italic</em></p>')
+ * // Returns: '**bold** and _italic_'
+ */
 export const htmlToMarkdownBasic = (html: string): string => {
   if (!html) {
     return '';

packages/shared/src/lib/strings.ts

@@ -113,3 +113,10 @@ export const stripHtmlTags = (html: string): string => {
 export const escapeMarkdown = (text: string): string => {
   return text.replace(/[\\`*_{}[\]()#+\-.!|]/g, '\\$&');
 };
+
+/**
+ * Regex to test if a string contains special characters.
+ * Matches any character that is NOT alphanumeric, underscore, or dot.
+ * Used for validating user input like emoji shortcuts or mentions.
+ */
+export const specialCharsRegex = /[^A-Za-z0-9_.]/;