Close #16: preserve white spaces in front of each line if preserveSpa…

…ce specified

README.md

@@ -5,8 +5,8 @@
 
 * List with checkbox
   * Add the data-line attribute to indicate which line the checkbox is in the markdown.
+* Support the `preserveSpace` option to work with WYSIWYG editors easier.
 * `TableSyntax`
-  * `escapeFoward` introduced for skiping pipe characters (`|`) that shall not be considered as a column separator.
   * `processCellContent` introduced for pre-processing cell's content
 * Link enhancements:
   * `LinkMapper` introduced to allow app for mapping to *application-specific* links.

lib/src/html_renderer.dart

@@ -41,17 +41,23 @@ String markdownToHtml(
     preserveSpace: preserveSpace,
   );
 
-  if (inlineOnly) return renderToHtml(document.parseInline(markdown));
+  if (inlineOnly) {
+    return renderToHtml(document.parseInline(markdown),
+        preserveSpace: preserveSpace);
+  }
 
   final nodes = document.parse(markdown);
 
-  return '${renderToHtml(nodes, enableTagfilter: enableTagfilter)}\n';
+  return '${renderToHtml(nodes, enableTagfilter: enableTagfilter,
+      preserveSpace: preserveSpace)}\n';
 }
 
 /// Renders [nodes] to HTML.
-String renderToHtml(List<Node> nodes, {bool enableTagfilter = false}) =>
+String renderToHtml(List<Node> nodes, {bool enableTagfilter = false,
+    bool preserveSpace = false}) =>
     HtmlRenderer(
       enableTagfilter: enableTagfilter,
+      preserveSpace: preserveSpace,
     ).render(nodes);
 
 const _blockTags = {
@@ -106,10 +112,13 @@ class CondensedHtmlRenderer implements NodeVisitor {
   final _elementStack = <Element>[];
   String? _lastVisitedTag;
   final bool _tagfilterEnabled;
+  final bool _spacePreserved;
 
   CondensedHtmlRenderer({
     bool enableTagfilter = false,
-  }) : _tagfilterEnabled = enableTagfilter;
+    bool preserveSpace = false,
+  }) : _tagfilterEnabled = enableTagfilter,
+    _spacePreserved = preserveSpace;
 
   String render(List<Node> nodes) {
     buffer = StringBuffer();
@@ -131,7 +140,7 @@ class CondensedHtmlRenderer implements NodeVisitor {
     }
     if (const {'br', 'p', 'li'}.contains(_lastVisitedTag)) {
       final lines = LineSplitter.split(content);
-      content = !_trimLeft || content.contains('<pre>')
+      content = _spacePreserved || content.contains('<pre>')
           ? lines.join('\n')
           : lines.map((line) => line.trimLeft()).join('\n');
       if (text.textContent.endsWith('\n')) {
@@ -164,9 +173,6 @@ class CondensedHtmlRenderer implements NodeVisitor {
     }
   }
 
-  /// Whether to trim left if it is contained in `p` or `li`
-  bool get _trimLeft => true;
-
   void _writeOpenTagStart(Element element) {
     buffer.write('<${element.tag}');
 
@@ -254,7 +260,7 @@ class CondensedHtmlRenderer implements NodeVisitor {
 
 /// Translates a parsed AST to HTML.
 class HtmlRenderer extends CondensedHtmlRenderer {
-  HtmlRenderer({super.enableTagfilter = false});
+  HtmlRenderer({super.enableTagfilter = false, super.preserveSpace = false});
 
   @override
   bool _isBlockTag(String? tag)
@@ -268,8 +274,8 @@ class HtmlRenderer extends CondensedHtmlRenderer {
 ///
 /// For better, you can use just [EmptyBlockSyntax] and [ParagraphSyntax].
 class TextRenderer extends HtmlRenderer {
-  @override
-  bool get _trimLeft => false; //preserve the spaces
+  TextRenderer(): super(preserveSpace: true);
+
   @override
   void _writeOpenTagStart(Element element) {
     if (_lastVisitedTag == 'p' && buffer.isNotEmpty) buffer.writeln();

test/markdown_test.dart

@@ -506,6 +506,27 @@ Line 2
 </ul>
 <p>
 Line 2</p>
+''');
+
+    validate(
+        'Space in front of line',
+        '''
+  Line 1
+
+* Item 1
+*  Item 2
+
+
+Line 2
+''', '''
+<p>  Line 1
+</p>
+<ul>
+<li>Item 1</li>
+<li> Item 2</li>
+</ul>
+<p>
+Line 2</p>
 ''');
 
   });