From 59090b82c32f369acf99add8ecb17f2884b8ee6f Mon Sep 17 00:00:00 2001
From: luke2x <97411838+luke2x@users.noreply.github.com>
Date: Sun, 18 Oct 2026 20:53:23 +0100
Subject: [PATCH] perf(mobile): walk HTML code ranges once when converting
 markdown

---
 apps/mobile/src/lib/markdownDocument.ts  |  7 ++++++-
 apps/mobile/src/lib/markdownHtml.test.ts | 22 ++++++++++++++++++++++
 2 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/apps/mobile/src/lib/markdownDocument.ts b/apps/mobile/src/lib/markdownDocument.ts
index 640a512dd4e51..db3b43a5726ca 100644
--- a/apps/mobile/src/lib/markdownDocument.ts
+++ b/apps/mobile/src/lib/markdownDocument.ts
@@ -101,8 +101,13 @@ export function markdownHtmlContent(content: string): string {
     codeRanges.push({ start: opening.index, end: closing.index + closing[0].length });
     index = closingIndex;
   }
+  let codeRangeIndex = 0;
   return content.replace(HTML_TAG, (tag, offset: number) => {
-    if (codeRanges.some((range) => offset >= range.start && offset < range.end)) return tag;
+    while (codeRanges[codeRangeIndex] && offset >= codeRanges[codeRangeIndex]!.end) {
+      codeRangeIndex += 1;
+    }
+    const range = codeRanges[codeRangeIndex];
+    if (range && offset >= range.start) return tag;
     if (tag.startsWith("<!--")) return "";
     if (/^<img\b/i.test(tag)) {
       const src = attribute(tag, "src");
diff --git a/apps/mobile/src/lib/markdownHtml.test.ts b/apps/mobile/src/lib/markdownHtml.test.ts
index a77a77e9a9cde..2633b43eb2f43 100644
--- a/apps/mobile/src/lib/markdownHtml.test.ts
+++ b/apps/mobile/src/lib/markdownHtml.test.ts
@@ -71,3 +71,25 @@ describe("HTML in native Markdown", () => {
     expect(result).toContain('`<img src="inline.png">`');
   });
 });
+
+it("keeps code literal across many ranges while converting HTML between and after them", () => {
+  const blocks = Array.from(
+    { length: 100 },
+    (_, index) => `\`<img src="literal-${index}.png">\` <img src="image-${index}.png">`,
+  );
+  const expected = Array.from(
+    { length: 100 },
+    (_, index) => `\`<img src="literal-${index}.png">\` ![](<image-${index}.png>)`,
+  );
+  expect(markdownHtmlContent(blocks.join("\n") + "<br>after")).toBe(
+    expected.join("\n") + "  \nafter",
+  );
+});
+
+it("keeps tags after an unclosed fence literal even when later inline ranges overlap it", () => {
+  const content =
+    '<div>before</div>\n```html\n<img src="one.png">\n`<img src="two.png">`\n<img src="three.png">';
+  expect(markdownHtmlContent(content)).toBe(
+    '\n\nbefore\n\n\n```html\n<img src="one.png">\n`<img src="two.png">`\n<img src="three.png">',
+  );
+});