Fix code blocks loosing the language hint on serialization

`prosemirror-markdown` uses `params` attribute for the language hint
whereas `tiptap` uses the `language` attribute.

Signed-off-by: Ferdinand Thiessen <[email protected]>

src/extensions/Markdown.js

@@ -1,9 +1,9 @@
-/*
+/**
  * @copyright Copyright (c) 2022 Max <[email protected]>
  *
  * @author Max <[email protected]>
  *
- * @license GNU AGPL version 3 or any later version
+ * @license AGPL-3.0-or-later
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU Affero General Public License as

src/extensions/RichText.js

@@ -28,7 +28,7 @@ import BulletList from './../nodes/BulletList.js'
 import Callout from './../nodes/Callouts.js'
 import CharacterCount from '@tiptap/extension-character-count'
 import Code from '@tiptap/extension-code'
-import CodeBlock from '@tiptap/extension-code-block'
+import CodeBlock from './../nodes/CodeBlock.js'
 import Document from '@tiptap/extension-document'
 import Dropcursor from '@tiptap/extension-dropcursor'
 import FrontMatter from './../nodes/FrontMatter.js'

src/nodes/CodeBlock.js

@@ -0,0 +1,14 @@
+import TiptapCodeBlock from '@tiptap/extension-code-block'
+import { defaultMarkdownSerializer } from 'prosemirror-markdown'
+
+const CodeBlock = TiptapCodeBlock.extend({
+
+	toMarkdown(state, node, parent, index) {
+		// prosemirror-markdown uses `params` instead of `language` attribute
+		node.attrs.params = node.attrs.language
+		return defaultMarkdownSerializer.nodes.code_block(state, node, parent, index)
+	},
+
+})
+
+export default CodeBlock

src/tests/markdown.spec.js

@@ -101,6 +101,8 @@ describe('Markdown though editor', () => {
 	})
 	test('code block', () => {
 		expect(markdownThroughEditor('```\n<?php echo "Hello World";\n```')).toBe('```\n<?php echo "Hello World";\n```')
+		// Issue #3328
+		expect(markdownThroughEditor('```python\nprint("Hello World")\n```')).toBe('```python\nprint("Hello World")\n```')
 	})
 	test('markdown untouched', () => {
 		// Issue #2703