feat(turndown-plugin-gfm): adopt MD060 compact style for table cells

Style compact avoids extra padding with a single space around cell
content:

| Character | Meaning |
| --- | --- |
| Y | Yes |
| N | No |

Closes #8795

apps/server/src/services/export/markdown.spec.ts

@@ -179,10 +179,10 @@ describe("Markdown export", () => {
             > [!IMPORTANT]
             > This is a very important information.
             >${space}
-            > |     |     |
+            > |  |  |
             > | --- | --- |
-            > | 1   | 2   |
-            > | 3   | 4   |
+            > | 1 | 2 |
+            > | 3 | 4 |
 
             > [!CAUTION]
             > This is a caution.
@@ -374,10 +374,10 @@ describe("Markdown export", () => {
             </figure>
         `;
         const expected = trimIndentation`\
-            |     |     |
+            |  |  |
             | --- | --- |
-            | Hi  | there |
-            | Hi  | there |`;
+            | Hi | there |
+            | Hi | there |`;
         expect(markdownExportService.toMarkdown(html)).toBe(expected);
     });
 

packages/turndown-plugin-gfm/src/lib/tables.js

@@ -96,7 +96,8 @@ rules.table = {
       var columnCount = tableColCount(node);
       var emptyHeader = ''
       if (columnCount && !secondLineIsDivider) {
-        emptyHeader = '|' + '     |'.repeat(columnCount) + '\n' + '|'
+        // MD060 compact style: 2 spaces between pipes for empty cells
+        emptyHeader = '|' + '  |'.repeat(columnCount) + '\n' + '|'
         for (var columnIndex = 0; columnIndex < columnCount; ++columnIndex) {
           emptyHeader += ' ' + getBorder(getColumnAlignment(node, columnIndex)) + ' |';
         }
@@ -157,13 +158,15 @@ function isFirstTbody (element) {
   )
 }
 
+// Format table cells following MD060 compact style:
+// Each cell has 1 space padding on left and right (prefix + content + ' |').
+// Empty cells result in 2 spaces between pipes (1 left + 1 right padding).
 function cell (content, node = null, index = null) {
   if (index === null) index = indexOf.call(node.parentNode.childNodes, node)
   var prefix = ' '
   if (index === 0) prefix = '| '
   let filteredContent = content.trim().replace(/\n\r/g, '<br>').replace(/\n/g, "<br>");
   filteredContent = filteredContent.replace(/\|+/g, '\\|')
-  while (filteredContent.length < 3) filteredContent += ' ';
   if (node) filteredContent = handleColSpan(filteredContent, node, ' ');
   return prefix + filteredContent + ' |'
 }
@@ -259,7 +262,7 @@ function nodeParentTable(node) {
 function handleColSpan(content, node, emptyChar) {
   const colspan = node.getAttribute('colspan') || 1;
   for (let i = 1; i < colspan; i++) {
-    content += ' | ' + emptyChar.repeat(3);
+    content += ' |' + emptyChar;
   }
   return content
 }

packages/turndown-plugin-gfm/test/index.html

@@ -141,11 +141,11 @@
 </div>
 <pre class="expected">| Column 1 | Column 2 | Column 3 | Column 4 |
 | --- | --- | --- | --- |
-|     | Row 1, Column 2 | Row 1, Column 3 | Row 1, Column 4 |
-| Row 2, Column 1 |     | Row 2, Column 3 | Row 2, Column 4 |
-| Row 3, Column 1 | Row 3, Column 2 |     | Row 3, Column 4 |
-| Row 4, Column 1 | Row 4, Column 2 | Row 4, Column 3 |     |
-|     |     |     | Row 5, Column 4 |</pre>
+|  | Row 1, Column 2 | Row 1, Column 3 | Row 1, Column 4 |
+| Row 2, Column 1 |  | Row 2, Column 3 | Row 2, Column 4 |
+| Row 3, Column 1 | Row 3, Column 2 |  | Row 3, Column 4 |
+| Row 4, Column 1 | Row 4, Column 2 | Row 4, Column 3 |  |
+|  |  |  | Row 5, Column 4 |</pre>
 </div>
 
 <div class="case" data-name="empty rows">
@@ -174,7 +174,7 @@
 <pre class="expected">| Heading 1 | Heading 2 |
 | --- | --- |
 | Row 1 | Row 1 |
-|     |     |
+|  |  |
 | Row 3 | Row 3 |</pre>
 </div>
 
@@ -259,7 +259,7 @@
       <tbody><tr><th>Heading</th></tr></tbody>
     </table>
   </div>
-  <pre class="expected">|     |
+  <pre class="expected">|  |
 | --- |
 | Heading |
 | --- |</pre>
@@ -272,7 +272,7 @@
       <tr><td>Row 2 Cell 1</td><td>Row 2 Cell 2</td></tr>
     </table>
   </div>
-  <pre class="expected">|     |     |
+  <pre class="expected">|  |  |
 | --- | --- |
 | Row 1 Cell 1 | Row 1 Cell 2 |
 | Row 2 Cell 1 | Row 2 Cell 2 |</pre>
@@ -291,7 +291,7 @@
       </tr>
     </table>
   </div>
-  <pre class="expected">|     |     |
+  <pre class="expected">|  |  |
 | --- | --- |
 | Heading | Not a heading |
 | Heading | Not a heading |</pre>