From 355ba754080dc3db620d03e87b6673920d0b73a3 Mon Sep 17 00:00:00 2001
From: Zihua Li <635902+luin@users.noreply.github.com>
Date: Sat, 20 Jul 2024 22:34:50 +0800
Subject: [PATCH] getSemanticHTML() exports white-space style when necessary

---
 packages/quill/src/core/editor.ts            | 17 ++++-
 packages/quill/test/unit/core/editor.spec.ts | 65 +++++++++++++++++++-
 2 files changed, 79 insertions(+), 3 deletions(-)

diff --git a/packages/quill/src/core/editor.ts b/packages/quill/src/core/editor.ts
index a19485840d..50a5c4a45d 100644
--- a/packages/quill/src/core/editor.ts
+++ b/packages/quill/src/core/editor.ts
@@ -360,6 +360,10 @@ function convertListHTML(
   return `</li></${endTag}>${convertListHTML(items, lastIndent - 1, types)}`;
 }
 
+const SPACE_EXCLUDE_NBSP = '[^\\S\\u00a0]';
+const COLLAPSIBLE_SPACES_REGEX = new RegExp(
+  `^${SPACE_EXCLUDE_NBSP}|${SPACE_EXCLUDE_NBSP}{2,}|${SPACE_EXCLUDE_NBSP}$`,
+);
 function convertHTML(
   blot: Blot,
   index: number,
@@ -370,7 +374,18 @@ function convertHTML(
     return blot.html(index, length);
   }
   if (blot instanceof TextBlot) {
-    return escapeText(blot.value().slice(index, index + length));
+    const escapedText = escapeText(blot.value().slice(index, index + length));
+
+    if (!COLLAPSIBLE_SPACES_REGEX.test(escapedText)) {
+      return escapedText;
+    }
+
+    const { parentElement } = blot.domNode;
+    const style =
+      parentElement?.ownerDocument.defaultView?.getComputedStyle(parentElement);
+    return style?.whiteSpace
+      ? `<span style="white-space:${style.whiteSpace}">${escapedText}</span>`
+      : escapedText;
   }
   if (blot instanceof ParentBlot) {
     // TODO fix API
diff --git a/packages/quill/test/unit/core/editor.spec.ts b/packages/quill/test/unit/core/editor.spec.ts
index 0c595332bb..0e09122e5f 100644
--- a/packages/quill/test/unit/core/editor.spec.ts
+++ b/packages/quill/test/unit/core/editor.spec.ts
@@ -28,9 +28,11 @@ import { ColorClass } from '../../../src/formats/color.js';
 import Quill from '../../../src/core.js';
 import { normalizeHTML } from '../__helpers__/utils.js';
 
-const createEditor = (html: string) => {
+const createEditor = (htmlOrContents: string | Delta) => {
   const container = document.createElement('div');
-  container.innerHTML = normalizeHTML(html);
+  if (typeof htmlOrContents === 'string') {
+    container.innerHTML = normalizeHTML(htmlOrContents);
+  }
   document.body.appendChild(container);
   const quill = new Quill(container, {
     registry: createRegistry([
@@ -54,9 +56,17 @@ const createEditor = (html: string) => {
       SizeClass,
     ]),
   });
+  if (typeof htmlOrContents !== 'string') {
+    quill.setContents(htmlOrContents);
+  }
   return quill.editor;
 };
 
+const applyWhiteSpace = (editor: Editor, whiteSpace: string) => {
+  editor.scroll.domNode.style.whiteSpace = whiteSpace;
+  return editor;
+};
+
 describe('Editor', () => {
   describe('insert', () => {
     test('text', () => {
@@ -1246,6 +1256,57 @@ describe('Editor', () => {
       );
     });
 
+    test('collapsible spaces', () => {
+      expect(
+        applyWhiteSpace(
+          createEditor('<p><strong>123 </strong>123<em> 123</em></p>'),
+          'pre-wrap',
+        ).getHTML(0, 11),
+      ).toEqual(
+        '<strong><span style="white-space:pre-wrap">123 </span></strong>123<em><span style="white-space:pre-wrap"> 123</span></em>',
+      );
+
+      expect(
+        applyWhiteSpace(
+          createEditor(new Delta().insert('1   2\n')),
+          'pre-wrap',
+        ).getHTML(0, 5),
+      ).toEqual('<span style="white-space:pre-wrap">1   2</span>');
+
+      expect(
+        applyWhiteSpace(
+          createEditor(
+            new Delta().insert('  123', { bold: true }).insert('\n'),
+          ),
+          'pre-wrap',
+        ).getHTML(0, 5),
+      ).toEqual(
+        '<strong><span style="white-space:pre-wrap">  123</span></strong>',
+      );
+    });
+
+    test('&nbsp;', () => {
+      expect(
+        applyWhiteSpace(
+          createEditor(
+            new Delta().insert('\u00a0 123', { bold: true }).insert('\n'),
+          ),
+          'pre-wrap',
+        ).getHTML(0, 5),
+      ).toEqual('<strong>\u00a0 123</strong>');
+
+      expect(
+        applyWhiteSpace(
+          createEditor(
+            new Delta().insert('\u00a0  123', { bold: true }).insert('\n'),
+          ),
+          'pre-wrap',
+        ).getHTML(0, 6),
+      ).toEqual(
+        '<strong><span style="white-space:pre-wrap">\u00a0  123</span></strong>',
+      );
+    });
+
     test('mixed list', () => {
       const editor = createEditor(
         `