fix: enable client parser to retain carriage return characters (#902)

* fix: enable client parser to retain carriage return characters

* fix: enable client parser to retain carriage return characters

* chore: only find \r not \n

* chore: add missing tests

* chore: add missing tests

src/client/domparser.ts

@@ -1,3 +1,5 @@
+import { escapeSpecialCharacters } from './utilities';
+
 // constants
 const HTML = 'html';
 const HEAD = 'head';
@@ -116,6 +118,9 @@ if (template && template.content) {
  * @returns - DOM nodes.
  */
 export default function domparser(html: string): NodeList {
+  // Escape special characters before parsing
+  html = escapeSpecialCharacters(html);
+
   const match = html.match(FIRST_TAG_REGEX);
   const firstTagName = match && match[1] ? match[1].toLowerCase() : '';
 

src/client/utilities.ts

@@ -51,6 +51,26 @@ function formatTagName(tagName: string): string {
   return tagName;
 }
 
+/**
+ * Escapes special characters before parsing.
+ *
+ * @param html - The HTML string.
+ * @returns - HTML string with escaped special characters.
+ */
+export function escapeSpecialCharacters(html: string): string {
+  return html.replace(/\r/g, '\\r');
+}
+
+/**
+ * Reverts escaped special characters back to actual characters.
+ *
+ * @param text - The text with escaped characters.
+ * @returns - Text with escaped characters reverted.
+ */
+export function revertEscapedCharacters(text: string): string {
+  return text.replace(/\\r/g, '\r');
+}
+
 /**
  * Transforms DOM nodes to `domhandler` nodes.
  *
@@ -95,7 +115,7 @@ export function formatDOM(
       }
 
       case 3:
-        current = new Text(node.nodeValue!);
+        current = new Text(revertEscapedCharacters(node.nodeValue!));
         break;
 
       case 8:

test/cases/html.js

@@ -305,6 +305,28 @@ module.exports = [
     data: ' ',
   },
 
+  // text with special characters
+  {
+    name: 'text with carriage return',
+    data: 'Hello\rWorld',
+  },
+  {
+    name: 'text with multiple carriage returns',
+    data: 'Hello\rDear\rWorld',
+  },
+  {
+    name: 'text with mixed newlines and carriage returns',
+    data: 'Hello\rWorld\nNew\rLine',
+  },
+  {
+    name: 'text with carriage return in tag',
+    data: '<div>Hello\rWorld</div>',
+  },
+  {
+    name: 'nested tags with carriage returns',
+    data: '<div>Hello\r<span>Beautiful\r</span>World</div>',
+  },
+
   // custom tag
   {
     name: 'custom tag',

test/server/client.test.ts

@@ -1,6 +1,8 @@
 import { expect } from 'chai';
 
 import { formatDOM } from '../../src/client/utilities';
+import { revertEscapedCharacters } from '../../src/client/utilities';
+import { escapeSpecialCharacters } from '../../src/client/utilities';
 
 describe('client utilities', () => {
   describe('formatDOM', () => {
@@ -10,4 +12,62 @@ describe('client utilities', () => {
       ).to.deep.equal([]);
     });
   });
+
+  describe('escapeSpecialCharacters', () => {
+    it('escapes carriage return characters', () => {
+      const input = 'Hello\rWorld';
+      const expected = 'Hello\\rWorld';
+      expect(escapeSpecialCharacters(input)).to.equal(expected);
+    });
+
+    it('does not modify strings without special characters', () => {
+      const input = 'Hello World';
+      expect(escapeSpecialCharacters(input)).to.equal(input);
+    });
+
+    it('handles empty strings', () => {
+      expect(escapeSpecialCharacters('')).to.equal('');
+    });
+
+    it('handles multiple carriage returns', () => {
+      const input = 'Hello\rDear\rWorld';
+      const expected = 'Hello\\rDear\\rWorld';
+      expect(escapeSpecialCharacters(input)).to.equal(expected);
+    });
+
+    it('only escapes carriage returns', () => {
+      const input = 'Hello\rWorld\n'; // \n should not be affected
+      const expected = 'Hello\\rWorld\n';
+      expect(escapeSpecialCharacters(input)).to.equal(expected);
+    });
+  });
+
+  describe('revertEscapedCharacters', () => {
+    it('reverts escaped carriage return characters', () => {
+      const input = 'Hello\\rWorld';
+      const expected = 'Hello\rWorld';
+      expect(revertEscapedCharacters(input)).to.equal(expected);
+    });
+
+    it('does not modify strings without escaped characters', () => {
+      const input = 'Hello World';
+      expect(revertEscapedCharacters(input)).to.equal(input);
+    });
+
+    it('handles empty strings', () => {
+      expect(revertEscapedCharacters('')).to.equal('');
+    });
+
+    it('handles multiple escaped carriage returns', () => {
+      const input = 'Hello\\rDear\\rWorld';
+      const expected = 'Hello\rDear\rWorld';
+      expect(revertEscapedCharacters(input)).to.equal(expected);
+    });
+
+    it('only reverts escaped carriage returns', () => {
+      const input = 'Hello\\rWorld\\n'; // \n should not be affected
+      const expected = 'Hello\rWorld\\n';
+      expect(revertEscapedCharacters(input)).to.equal(expected);
+    });
+  });
 });