Don't copy empty elements that were not selected on purpose as GFM

3 files changed, 55 insertions, 29 deletions

diff --git a/app/assets/javascripts/copy_as_gfm.js b/app/assets/javascripts/copy_as_gfm.js
index 570799c030e..8ded09a7cc1 100644
--- a/app/assets/javascripts/copy_as_gfm.js
+++ b/app/assets/javascripts/copy_as_gfm.js
@@ -18,12 +18,12 @@ const gfmRules = {
     },
   },
   TaskListFilter: {
-    'input[type=checkbox].task-list-item-checkbox'(el, text) {
+    'input[type=checkbox].task-list-item-checkbox'(el) {
       return `[${el.checked ? 'x' : ' '}]`;
     },
   },
   ReferenceFilter: {
-    '.tooltip'(el, text) {
+    '.tooltip'(el) {
       return '';
     },
     'a.gfm:not([data-link=true])'(el, text) {
@@ -39,15 +39,15 @@ const gfmRules = {
     },
   },
   TableOfContentsFilter: {
-    'ul.section-nav'(el, text) {
+    'ul.section-nav'(el) {
       return '[[_TOC_]]';
     },
   },
   EmojiFilter: {
-    'img.emoji'(el, text) {
+    'img.emoji'(el) {
       return el.getAttribute('alt');
     },
-    'gl-emoji'(el, text) {
+    'gl-emoji'(el) {
       return `:${el.getAttribute('data-name')}:`;
     },
   },
@@ -57,13 +57,13 @@ const gfmRules = {
     },
   },
   VideoLinkFilter: {
-    '.video-container'(el, text) {
+    '.video-container'(el) {
       const videoEl = el.querySelector('video');
       if (!videoEl) return false;
 
       return CopyAsGFM.nodeToGFM(videoEl);
     },
-    'video'(el, text) {
+    'video'(el) {
       return `![${el.dataset.title}](${el.getAttribute('src')})`;
     },
   },
@@ -74,19 +74,19 @@ const gfmRules = {
     'code.code.math[data-math-style=inline]'(el, text) {
       return `$\`${text}\`$`;
     },
-    'span.katex-display span.katex-mathml'(el, text) {
+    'span.katex-display span.katex-mathml'(el) {
       const mathAnnotation = el.querySelector('annotation[encoding="application/x-tex"]');
       if (!mathAnnotation) return false;
 
       return `\`\`\`math\n${CopyAsGFM.nodeToGFM(mathAnnotation)}\n\`\`\``;
     },
-    'span.katex-mathml'(el, text) {
+    'span.katex-mathml'(el) {
       const mathAnnotation = el.querySelector('annotation[encoding="application/x-tex"]');
       if (!mathAnnotation) return false;
 
       return `$\`${CopyAsGFM.nodeToGFM(mathAnnotation)}\`$`;
     },
-    'span.katex-html'(el, text) {
+    'span.katex-html'(el) {
       // We don't want to include the content of this element in the copied text.
       return '';
     },
@@ -95,7 +95,7 @@ const gfmRules = {
     },
   },
   SanitizationFilter: {
-    'a[name]:not([href]):empty'(el, text) {
+    'a[name]:not([href]):empty'(el) {
       return el.outerHTML;
     },
     'dl'(el, text) {
@@ -143,7 +143,7 @@ const gfmRules = {
     },
   },
   MarkdownFilter: {
-    'br'(el, text) {
+    'br'(el) {
       // Two spaces at the end of a line are turned into a BR
       return '  ';
     },
@@ -162,7 +162,7 @@ const gfmRules = {
     'blockquote'(el, text) {
       return text.trim().split('\n').map(s => `> ${s}`.trim()).join('\n');
     },
-    'img'(el, text) {
+    'img'(el) {
       return `![${el.getAttribute('alt')}](${el.getAttribute('src')})`;
     },
     'a.anchor'(el, text) {
@@ -222,10 +222,10 @@ const gfmRules = {
     'sup'(el, text) {
       return `^${text}`;
     },
-    'hr'(el, text) {
+    'hr'(el) {
       return '-----';
     },
-    'table'(el, text) {
+    'table'(el) {
       const theadEl = el.querySelector('thead');
       const tbodyEl = el.querySelector('tbody');
       if (!theadEl || !tbodyEl) return false;
@@ -233,11 +233,11 @@ const gfmRules = {
       const theadText = CopyAsGFM.nodeToGFM(theadEl);
       const tbodyText = CopyAsGFM.nodeToGFM(tbodyEl);
 
-      return theadText + tbodyText;
+      return [theadText, tbodyText].join('\n');
     },
     'thead'(el, text) {
       const cells = _.map(el.querySelectorAll('th'), (cell) => {
-        let chars = CopyAsGFM.nodeToGFM(cell).trim().length + 2;
+        let chars = CopyAsGFM.nodeToGFM(cell).length + 2;
 
         let before = '';
         let after = '';
@@ -262,10 +262,15 @@ const gfmRules = {
         return before + middle + after;
       });
 
-      return `${text}|${cells.join('|')}|`;
+      const separatorRow = `|${cells.join('|')}|`;
+
+      return [text, separatorRow].join('\n');
     },
-    'tr'(el, text) {
-      const cells = _.map(el.querySelectorAll('td, th'), cell => CopyAsGFM.nodeToGFM(cell).trim());
+    'tr'(el) {
+      const cellEls = el.querySelectorAll('td, th');
+      if (cellEls.length === 0) return false;
+
+      const cells = _.map(cellEls, cell => CopyAsGFM.nodeToGFM(cell));
       return `| ${cells.join(' | ')} |`;
     },
   },
@@ -343,7 +348,9 @@ class CopyAsGFM {
     return codeEl;
   }
 
-  static nodeToGFM(node) {
+  static nodeToGFM(node, respectWhitespaceParam = false) {
+    let respectWhitespace = respectWhitespaceParam;
+
     if (node.nodeType === Node.COMMENT_NODE) {
       return '';
     }
@@ -352,7 +359,9 @@ class CopyAsGFM {
       return node.textContent;
     }
 
-    const text = this.innerGFM(node);
+    respectWhitespace = respectWhitespace || (node.nodeName === 'PRE' || node.nodeName === 'CODE');
+
+    const text = this.innerGFM(node, respectWhitespace);
 
     if (node.nodeType === Node.DOCUMENT_FRAGMENT_NODE) {
       return text;
@@ -366,7 +375,17 @@ class CopyAsGFM {
 
         if (!window.gl.utils.nodeMatchesSelector(node, selector)) continue;
 
-        const result = func(node, text);
+        let result;
+        if (func.length === 2) {
+          // if `func` takes 2 arguments, it depends on text.
+          // if there is no text, we don't need to generate GFM for this node.
+          if (text.length === 0) continue;
+
+          result = func(node, text);
+        } else {
+          result = func(node);
+        }
+
         if (result === false) continue;
 
         return result;
@@ -376,7 +395,7 @@ class CopyAsGFM {
     return text;
   }
 
-  static innerGFM(parentNode) {
+  static innerGFM(parentNode, respectWhitespace = false) {
     const nodes = parentNode.childNodes;
 
     const clonedParentNode = parentNode.cloneNode(true);
@@ -386,13 +405,19 @@ class CopyAsGFM {
       const node = nodes[i];
       const clonedNode = clonedNodes[i];
 
-      const text = this.nodeToGFM(node);
+      const text = this.nodeToGFM(node, respectWhitespace);
 
       // `clonedNode.replaceWith(text)` is not yet widely supported
       clonedNode.parentNode.replaceChild(document.createTextNode(text), clonedNode);
     }
 
-    return clonedParentNode.innerText || clonedParentNode.textContent;
+    let nodeText = clonedParentNode.innerText || clonedParentNode.textContent;
+
+    if (!respectWhitespace) {
+      nodeText = nodeText.trim();
+    }
+
+    return nodeText;
   }
 }
 
diff --git a/changelogs/unreleased/dm-copy-as-gfm-without-empty-elements.yml b/changelogs/unreleased/dm-copy-as-gfm-without-empty-elements.yml
new file mode 100644
index 00000000000..45a61320ff2
--- /dev/null
+++ b/changelogs/unreleased/dm-copy-as-gfm-without-empty-elements.yml
@@ -0,0 +1,4 @@
+---
+title: Don't copy empty elements that were not selected on purpose as GFM
+merge_request:
+author:
diff --git a/spec/features/copy_as_gfm_spec.rb b/spec/features/copy_as_gfm_spec.rb
index be615519a09..b6c51569bdc 100644
--- a/spec/features/copy_as_gfm_spec.rb
+++ b/spec/features/copy_as_gfm_spec.rb
@@ -51,7 +51,6 @@ describe 'Copy as GFM', feature: true, js: true do
 
           To see how GitLab looks please see the [features page on our website](https://about.gitlab.com/features/).
 
-
           - Manage Git repositories with fine grained access controls that keep your code secure
 
           - Perform code reviews and enhance collaboration with merge requests
@@ -352,7 +351,6 @@ describe 'Copy as GFM', feature: true, js: true do
         <<-GFM.strip_heredoc,
           - Nested
 
-
               - Lists
         GFM
 
@@ -375,7 +373,6 @@ describe 'Copy as GFM', feature: true, js: true do
         <<-GFM.strip_heredoc,
           1. Nested
 
-
               1. Numbered lists
         GFM