Fix hard line breaks displayed with additional new line between

src/markdownit/index.js

@@ -16,4 +16,7 @@ const markdownit = MarkdownIt('commonmark', { html: false, breaks: false })
 	.use(keepSyntax)
 	.use(markdownitMentions)
 
+// Issue #3370: To preserve softbreaks within md files we preserve all whitespaces, so we must not introduce additional new lines after a <br> element
+markdownit.renderer.rules.hardbreak = (tokens, idx, options) => (options.xhtmlOut ? '<br />' : '<br>')
+
 export default markdownit

src/tests/markdown.spec.js

@@ -34,6 +34,7 @@ describe('Commonmark', () => {
 		// https://github.com/markdown-it/markdown-it/blob/df4607f1d4d4be7fdc32e71c04109aea8cc373fa/test/commonmark.js#L10
 		return str.replace(/<blockquote><\/blockquote>/g, '<blockquote>\n</blockquote>')
 			.replace(/<span class="keep-md">([^<]+)<\/span>/g, '$1')
+			.replace(/<br \/>/, '<br />\n')
 	}
 
 	spec.forEach((entry) => {

src/tests/tables.spec.js → src/tests/nodes/Table.spec.js

@@ -1,11 +1,11 @@
-import { createEditor } from './../EditorFactory'
-import { createMarkdownSerializer } from './../extensions/Markdown'
-import markdownit from './../markdownit'
-import input from './fixtures/table.md'
-import output from './fixtures/tables/basic.out.html'
-import otherStructure from './fixtures/tableWithOtherStructure.html'
-import handbook from './fixtures/tables/handbook.html'
-import handbookOut from './fixtures/tables/handbook.out.html'
+import { createEditor } from '../../EditorFactory'
+import { createMarkdownSerializer } from '../../extensions/Markdown'
+import markdownit from '../../markdownit'
+import input from '../fixtures/table.md'
+import output from '../fixtures/tables/basic.out.html'
+import otherStructure from '../fixtures/tableWithOtherStructure.html'
+import handbook from '../fixtures/tables/handbook.html'
+import handbookOut from '../fixtures/tables/handbook.out.html'
 
 describe('Table', () => {
 

src/tests/tiptap.spec.js

@@ -0,0 +1,23 @@
+import createEditor from '../EditorFactory'
+import markdownit from '../markdownit'
+
+const renderedHTML = ( markdown ) => {
+    const editor = createEditor({
+        content: markdownit.render(markdown),
+        enableRichEditing: true
+    })
+    // Remove TrailingNode
+    return editor.getHTML().replace(/<p><\/p>$/, '')
+}
+
+describe('TipTap', () => {
+	it('render softbreaks', () => {
+        const markdown = 'This\nis\none\nparagraph'
+		expect(renderedHTML(markdown)).toEqual(`<p>${markdown}</p>`)
+	})
+
+    it('render hardbreak', () => {
+        const markdown = 'Hard line break  \nNext Paragraph'
+        expect(renderedHTML(markdown)).toEqual('<p>Hard line break<br>Next Paragraph</p>')
+    })
+})