From c057fb389f4f6967e86e439eb59e4d1851cd7250 Mon Sep 17 00:00:00 2001
From: EnixCoda <enixcoda@gmail.com>
Date: Wed, 11 Nov 2020 17:13:29 +0800
Subject: [PATCH] chore: remove leading space when copy file

---
 src/platforms/GitHub/CopyFileButton.tsx |  2 +-
 src/utils/DOMHelper.ts                  | 29 ++++++++++++++++++-------
 2 files changed, 22 insertions(+), 9 deletions(-)

diff --git a/src/platforms/GitHub/CopyFileButton.tsx b/src/platforms/GitHub/CopyFileButton.tsx
index d7ec994..753191b 100644
--- a/src/platforms/GitHub/CopyFileButton.tsx
+++ b/src/platforms/GitHub/CopyFileButton.tsx
@@ -34,7 +34,7 @@ export function CopyFileButton(props: React.PropsWithChildren<Props>) {
       function copyCode() {
         const codeElement = getCodeElement()
         if (codeElement) {
-          setContent(copyElementContent(codeElement) ? contents.success : contents.error)
+          setContent(copyElementContent(codeElement, true) ? contents.success : contents.error)
         }
       }
       element.addEventListener('click', copyCode)
diff --git a/src/utils/DOMHelper.ts b/src/utils/DOMHelper.ts
index a6bfdcc..38f9fcd 100644
--- a/src/utils/DOMHelper.ts
+++ b/src/utils/DOMHelper.ts
@@ -73,16 +73,29 @@ export function scrollToRepoContent() {
 /**
  * copy content of a DOM element to clipboard
  */
-export function copyElementContent(element: Element): boolean {
-  let selection = window.getSelection()
-  if (selection) selection.removeAllRanges()
+export function copyElementContent(element: Element, trimLeadingSpace?: boolean): boolean {
+  window.getSelection()?.removeAllRanges()
+
   const range = document.createRange()
-  range.selectNode(element)
-  selection = window.getSelection()
-  if (selection) selection.addRange(range)
+  if (trimLeadingSpace) {
+    // Leading spaces can be produced by embedded DOM structures
+    let realWrapper: Element | null = element
+    while (realWrapper?.childElementCount === 1) realWrapper = realWrapper?.firstElementChild
+    if (realWrapper?.childElementCount && realWrapper.childElementCount > 1) {
+      const first = realWrapper.firstElementChild
+      const last = realWrapper.lastElementChild
+      if (first && last) {
+        range.selectNode(first)
+        range.setEndAfter(last)
+      }
+    }
+  } else {
+    range.selectNode(element)
+  }
+
+  window.getSelection()?.addRange(range)
   const isCopySuccessful = document.execCommand('copy')
-  selection = window.getSelection()
-  if (selection) selection.removeAllRanges()
+  window.getSelection()?.removeAllRanges()
   return isCopySuccessful
 }