refactor: Improve linebreak logic for html messages

famedly · Feb 6, 2025 · d255b8b · d255b8b
1 parent 41a9fbc
commit d255b8b
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Showing 2 changed files with 28 additions and 7 deletions.
diff --git a/lib/src/utils/markdown.dart b/lib/src/utils/markdown.dart
@@ -211,6 +211,15 @@ String markdown(
   String? Function(String)? getMention,
   bool convertLinebreaks = true,
 }) {
+  // Workaround to keep linebreaks. We add a **Zero Width Space** in all
+  // empty lines to keep the lines as the user added them and workaround the
+  // markdown rules for multiple empty lines.
+  text = text
+      .trim()
+      .split('\n')
+      .map((line) => line.isEmpty ? '\u200B' : line)
+      .join('\n');
+
   var ret = markdownToHtml(
     text,
     extensionSet: ExtensionSet.commonMark,
@@ -225,7 +234,7 @@ String markdown(
       MentionSyntax(getMention),
       InlineLatexSyntax(),
     ],
-  );
+  ).replaceAll('\u200B', ''); // Remove all Zero-Width Non-Joiners afterwards!
 
   var stripPTags = '<p>'.allMatches(ret).length <= 1;
   if (stripPTags) {

diff --git a/test/markdown_test.dart b/test/markdown_test.dart
@@ -70,14 +70,26 @@ void main() {
         'Snape killed <span data-mx-spoiler="">Dumbledoor <strong>bold</strong></span>',
       );
     });
-    test('multiple paragraphs', () {
-      expect(markdown('Heya!\n\nBeep'), '<p>Heya!</p><p>Beep</p>');
+    test('linebreaks', () {
+      expect(markdown('Heya!\nBeep'), 'Heya!<br/>Beep');
+      expect(markdown('Heya!\n\nBeep'), 'Heya!<br/><br/>Beep');
+      expect(markdown('Heya!\n\n\nBeep'), 'Heya!<br/><br/><br/>Beep');
+      expect(markdown('Heya!\n\n\n\nBeep'), 'Heya!<br/><br/><br/><br/>Beep');
+      expect(
+        markdown('Heya!\n\n\n\nBeep\n\n'),
+        'Heya!<br/><br/><br/><br/>Beep',
+      );
+      expect(
+        markdown('\n\nHeya!\n\n\n\nBeep'),
+        'Heya!<br/><br/><br/><br/>Beep',
+      );
+      expect(
+        markdown('\n\nHeya!\n\n\n\nBeep\n '),
+        'Heya!<br/><br/><br/><br/>Beep',
+      );
     });
     test('Other block elements', () {
-      expect(markdown('# blah\n\nblubb'), '<h1>blah</h1><p>blubb</p>');
-    });
-    test('linebreaks', () {
-      expect(markdown('foxies\ncute'), 'foxies<br/>cute');
+      expect(markdown('# blah\n\nblubb'), '<h1>blah</h1><p><br/>blubb</p>');
     });
     test('lists', () {
       expect(