update note content

src/utils/markdown.ts

@@ -1,7 +1,8 @@
 import { marked } from 'marked'
 import DOMPurify from 'dompurify'
+import Turndown from 'turndown'
 
-export function mdToHtml(mdText: string) {
+export function mdToHtml(mdText: string): string {
   const renderer = new marked.Renderer()
 
   const html = DOMPurify.sanitize(marked.parse(mdText, { renderer }))
@@ -14,3 +15,28 @@ export function mdToHtml(mdText: string) {
   })
   return doc.body.innerHTML
 }
+
+export function htmlToMd(htmlText: string): string {
+  const turndown = new Turndown({ headingStyle: 'atx' })
+  const escapes = [
+    [/\\/g, '\\\\'],
+    [/\*/g, '\\*'],
+    [/^-/g, '\\-'],
+    [/^\+ /g, '\\+ '],
+    [/^(=+)/g, '\\$1'],
+    [/^(#{1,6}) /g, '\\$1 '],
+    [/`/g, '\\`'],
+    [/^~~~/g, '\\~~~'],
+    // [/\[/g, '\\['],
+    // [/\]/g, '\\]'],
+    [/^>/g, '\\>'],
+    [/_/g, '\\_'],
+    [/^(\d+)\. /g, '$1\\. '],
+  ]
+  turndown.escape = (string) =>
+    escapes.reduce((accumulator, escape) => {
+      return accumulator.replace(escape[0], escape[1] as string)
+    }, string)
+  const md = turndown.turndown(htmlText)
+  return md
+}