feat: convert pasted markdown to html so that it is correctly rendered (#3041)

Resolves https://community.vikunja.io/t/markdown-as-first-class-citizen/2975/4

Reviewed-on: https://kolaente.dev/vikunja/vikunja/pulls/3041
Co-authored-by: kolaente <k@knt.li>
Co-committed-by: kolaente <k@knt.li>

frontend/package.json

@@ -93,6 +93,7 @@
     "is-touch-device": "1.0.1",
     "klona": "2.0.6",
     "lowlight": "3.3.0",
+    "marked": "^15.0.6",
     "pinia": "2.3.1",
     "register-service-worker": "1.7.2",
     "sortablejs": "1.15.6",

frontend/pnpm-lock.yaml

@@ -148,6 +148,9 @@ importers:
       lowlight:
         specifier: 3.3.0
         version: 3.3.0
+      marked:
+        specifier: ^15.0.6
+        version: 15.0.6
       pinia:
         specifier: 2.3.1
         version: 2.3.1(typescript@5.7.3)(vue@3.5.13(typescript@5.7.3))
@@ -4754,6 +4757,11 @@ packages:
     resolution: {integrity: sha512-a54IwgWPaeBCAAsv13YgmALOF1elABB08FxO9i+r4VFk5Vl4pKokRPeX8u5TCgSsPi6ec1otfLjdOpVcgbpshg==}
     hasBin: true
 
+  marked@15.0.6:
+    resolution: {integrity: sha512-Y07CUOE+HQXbVDCGl3LXggqJDbXDP2pArc2C1N1RRMN0ONiShoSsIInMd5Gsxupe7fKLpgimTV+HOJ9r7bA+pg==}
+    engines: {node: '>= 18'}
+    hasBin: true
+
   mdn-data@2.0.28:
     resolution: {integrity: sha512-aylIc7Z9y4yzHYAJNuESG3hfhC+0Ibp/MAMiaOZgNv4pmEdFyfZhhhny4MNiAfWdBQ1RQ2mfDWmM1x8SvGyp8g==}
 
@@ -11719,6 +11727,8 @@ snapshots:
       punycode.js: 2.3.1
       uc.micro: 2.1.0
 
+  marked@15.0.6: {}
+
   mdn-data@2.0.28: {}
 
   mdn-data@2.0.30: {}

frontend/src/components/input/editor/TipTap.vue

@@ -146,6 +146,8 @@ import EditorToolbar from './EditorToolbar.vue'
 import StarterKit from '@tiptap/starter-kit'
 import {Extension, mergeAttributes} from '@tiptap/core'
 import {BubbleMenu, EditorContent, type Extensions, useEditor} from '@tiptap/vue-3'
+import {Plugin, PluginKey} from '@tiptap/pm/state'
+import {marked} from 'marked'
 
 import Link from '@tiptap/extension-link'
 import CodeBlockLowlight from '@tiptap/extension-code-block-lowlight'
@@ -327,6 +329,32 @@ const additionalLinkProtocols = [
 	'notion',
 ]
 
+const MarkdownPasteHandler = Extension.create({
+	name: 'markdownPasteHandler',
+
+	addProseMirrorPlugins() {
+		return [
+			new Plugin({
+				key: new PluginKey('markdownPasteHandler'),
+				props: {
+					handlePaste: (view, event) => {
+						const text = event.clipboardData?.getData('text/plain')
+						if (!text) return false
+
+						const html = marked.parse(text)
+
+						// It is fine to paste the content without sanitizing because it will be sanitized later by TipTap
+						this.editor.commands.insertContent(html)
+						// https://github.com/ueberdosis/tiptap/discussions/4118#discussioncomment-8931999
+						return true
+					},
+				},
+			}),
+		]
+	},
+})
+
+
 const extensions : Extensions = [
 	// Starterkit:
 	StarterKit.configure({
@@ -418,6 +446,8 @@ const extensions : Extensions = [
 	Commands.configure({
 		suggestion: suggestionSetup(t),
 	}),
+	
+	MarkdownPasteHandler,
 ]
 
 // Add a custom extension for the Escape key