Improve support for linebreaks, tables and nested blockquotes in lists

app/assets/javascripts/copy_as_gfm.js.es6

@@ -92,9 +92,6 @@
       },
     },
     SanitizationFilter: {
-      'br'(el, text) {
-        return '<br>';
-      },
       'dl'(el, text) {
         let lines = text.trim().split('\n');
         // Add two spaces to the front of subsequent list items lines,
@@ -127,6 +124,10 @@
       },
     },
     MarkdownFilter: {
+      'br'(el, text) {
+        // Two spaces at the end of a line are turned into a BR
+        return '  ';
+      },
       'code'(el, text) {
         let backtickCount = 1;
         const backtickMatch = text.match(/`+/);
@@ -155,7 +156,7 @@
       'li'(el, text) {
         const lines = text.trim().split('\n');
         const firstLine = `- ${lines.shift()}`;
-        // Add two spaces to the front of subsequent list items lines,
+        // Add four spaces to the front of subsequent list items lines,
         // or leave the line entirely blank.
         const nextLines = lines.map((s) => {
           if (s.trim().length === 0) return '';
@@ -213,7 +214,7 @@
       },
       'thead'(el, text) {
         const cells = _.map(el.querySelectorAll('th'), (cell) => {
-          let chars = CopyAsGFM.nodeToGFM(cell).trim().length;
+          let chars = CopyAsGFM.nodeToGFM(cell).trim().length + 2;
 
           let before = '';
           let after = '';
@@ -231,14 +232,14 @@
               break;
           }
 
-          chars = Math.max(chars, 0);
+          chars = Math.max(chars, 3);
 
           const middle = Array(chars + 1).join('-');
 
           return before + middle + after;
         });
 
-        return `${text}| ${cells.join(' | ')} |`;
+        return `${text}|${cells.join('|')}|`;
       },
       'tr'(el, text) {
         const cells = _.map(el.querySelectorAll('td, th'), cell => CopyAsGFM.nodeToGFM(cell).trim());

spec/features/copy_as_gfm_spec.rb

@@ -236,8 +236,6 @@ describe 'Copy as GFM', feature: true, js: true do
   it 'supports SanitizationFilter' do
     verify(
       <<-GFM.strip_heredoc
-      BR: <br>
-
       <sub>sub</sub>
 
       <dl>
@@ -284,6 +282,8 @@ describe 'Copy as GFM', feature: true, js: true do
 
   it 'supports MarkdownFilter' do
     verify(
+      "Line with two spaces at the end  \nto insert a linebreak",
+
       '`code`',
       '`` code with ` ticks ``',
 
@@ -319,6 +319,13 @@ describe 'Copy as GFM', feature: true, js: true do
             - Lists
       GFM
 
+      # list with blockquote
+      <<-GFM.strip_heredoc,
+        - List
+
+            > Blockquote
+      GFM
+
       '1. Numbered list item',
 
       # multiline numbered list item
@@ -355,10 +362,18 @@ describe 'Copy as GFM', feature: true, js: true do
       # table
       <<-GFM.strip_heredoc,
         | Centered | Right | Left |
-        | :------: | ----: | ---- |
+        |:--------:|------:|------|
         | Foo | Bar | **Baz** |
         | Foo | Bar | **Baz** |
       GFM
+
+      # table with empty heading
+      <<-GFM.strip_heredoc,
+        |  | x | y |
+        |---|---|---|
+        | a | 1 | 0 |
+        | b | 0 | 1 |
+      GFM
     )
   end