refactor Post.jsx with memoization

src/components/Post.jsx

@@ -1,18 +1,21 @@
-import React from 'react';
+import React, { useMemo } from 'react';
 import ReactMarkdown from 'react-markdown';
 import { Link } from 'react-router-dom';
 import rehypeSanitize, { defaultSchema } from 'rehype-sanitize';
 import breaks from 'remark-breaks';
 
 
-const customSchema = {
+const Post = ({ content }) => {
+  const doubleNewlineContent = useMemo(() => content?.replaceAll(/\n(?!\n)/g, '\n\n'), [content]);
+
+  const customSchema = useMemo(() => ({
     ...defaultSchema,
     tagNames: [...defaultSchema.tagNames, 'div'],
     attributes: {
       ...defaultSchema.attributes,
       div: ['className'],
     },
-};
+  }), []);
 
 
   const blockquoteToGreentext = () => (tree) => {
@@ -91,10 +94,6 @@ const createQuotelink = (children) => {
   };
 
 
-
-const Post = ({ content }) => {
-  const doubleNewlineContent = content?.replaceAll(/\n(?!\n)/g, '\n\n');
-
   return (
     <ReactMarkdown
       children={doubleNewlineContent}