Fix backticks escaped inside code blocks

src/markdown.ts

@@ -640,12 +640,15 @@ export function createMarkdownContent(content: string, url: string) {
 				|| '';
 			const code = codeElement.textContent || '';
 
-			// Clean up the content and escape backticks
-			const cleanCode = code
-				.trim()
-				.replace(/`/g, '\\`');
-
-			return `\n\`\`\`${language}\n${cleanCode}\n\`\`\`\n`;
+			// Backslash escapes are literal inside a fence, so escaping backticks here would
+			// corrupt the code. Only a line-leading run of three or more backticks can close
+			// the block, so grow the fence past the longest such run instead.
+			const cleanCode = code.trim();
+			const fenceSize = (cleanCode.match(/^`{3,}/gm) || [])
+				.reduce((size, run) => Math.max(size, run.length + 1), 3);
+			const fence = '`'.repeat(fenceSize);
+
+			return `\n${fence}${language}\n${cleanCode}\n${fence}\n`;
 		}
 	});
 

tests/expected/general--obsidian.md-blog-verify-obsidian-sync-encryption.md

@@ -38,7 +38,7 @@ First, get the salt used to derive your encryption key by following these steps:
 let data = await (await fetch('https://api.obsidian.md/vault/list', {method:'POST', headers: {'Content-Type':'application/json'}, body: JSON.stringify({token: JSON.parse(localStorage.getItem('obsidian-account')).token})})).json();
 let vaults = [].concat(data.shared, data.vaults);
 let vault = vaults.find(v => v.id === app.internalPlugins.getEnabledPluginById('sync').vaultId);
-console.log(\`The salt of your vault ${vault.name} is: "${vault.salt}" with encryptionVersion ${vault.encryption_version}\`);
+console.log(`The salt of your vault ${vault.name} is: "${vault.salt}" with encryptionVersion ${vault.encryption_version}`);
 ```
 
 You should see a message containing your salt and encryption version:

tests/markdown.test.ts

@@ -294,4 +294,43 @@ describe('Markdown conversion', () => {
 			expect(markdown).not.toContain('\\begin{aligned}');
 		});
 	});
+
+	describe('fenced code blocks', () => {
+		test('should not escape backticks inside a code block', () => {
+			const markdown = createMarkdownContent(
+				'<article><pre><code class="language-javascript">res.write(`data: ${payload}`);</code></pre></article>',
+				'https://example.com'
+			);
+
+			expect(markdown).toContain('res.write(`data: ${payload}`);');
+			expect(markdown).not.toContain('\\`');
+		});
+
+		test('should lengthen the fence when the code contains a fence line', () => {
+			const markdown = createMarkdownContent(
+				'<article><pre><code class="language-markdown">```js\nconst a = 1;\n```</code></pre></article>',
+				'https://example.com'
+			);
+
+			expect(markdown).toContain('````markdown\n```js\nconst a = 1;\n```\n````');
+		});
+
+		test('should size the fence past the longest fence line in the code', () => {
+			const markdown = createMarkdownContent(
+				'<article><pre><code>a\n`````\nb</code></pre></article>',
+				'https://example.com'
+			);
+
+			expect(markdown).toContain('``````\na\n`````\nb\n``````');
+		});
+
+		test('should keep the standard fence for code without backticks', () => {
+			const markdown = createMarkdownContent(
+				'<article><pre><code class="language-python">print("hi")</code></pre></article>',
+				'https://example.com'
+			);
+
+			expect(markdown).toContain('```python\nprint("hi")\n```');
+		});
+	});
 });