diff --git a/packages/quill/src/core/editor.ts b/packages/quill/src/core/editor.ts
index a19485840d..ed93366ed5 100644
--- a/packages/quill/src/core/editor.ts
+++ b/packages/quill/src/core/editor.ts
@@ -370,7 +370,8 @@ 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));
+    return escapedText.replace(/\s/g, ' ');
   }
   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..2d47a1dec9 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([
@@ -54,6 +56,9 @@ const createEditor = (html: string) => {
       SizeClass,
     ]),
   });
+  if (typeof htmlOrContents !== 'string') {
+    quill.setContents(htmlOrContents);
+  }
   return quill.editor;
 };
 
@@ -1246,6 +1251,25 @@ describe('Editor', () => {
       );
     });
 
+    test('collapsible spaces', () => {
+      expect(
+        createEditor('<p><strong>123 </strong>123<em> 123</em></p>').getHTML(
+          0,
+          11,
+        ),
+      ).toEqual('<strong>123&nbsp;</strong>123<em>&nbsp;123</em>');
+
+      expect(createEditor(new Delta().insert('1   2\n')).getHTML(0, 5)).toEqual(
+        '1&nbsp;&nbsp;&nbsp;2',
+      );
+
+      expect(
+        createEditor(
+          new Delta().insert('  123', { bold: true }).insert('\n'),
+        ).getHTML(0, 5),
+      ).toEqual('<strong>&nbsp;&nbsp;123</strong>');
+    });
+
     test('mixed list', () => {
       const editor = createEditor(
         `