From 4cd09653652892c8d4193464ba28eeb5d31f4470 Mon Sep 17 00:00:00 2001
From: Tom Heaton <thomas.m.heaton@gmail.com>
Date: Mon, 28 Sep 2026 11:25:11 +0100
Subject: [PATCH] fix: don't throw when history.state is null after
 replaceState

---
 .changeset/null-history-state-depth.md |  5 +++++
 src/routers/history.ts                 |  2 +-
 test/browser-history.spec.ts           | 13 +++++++++++++
 3 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/null-history-state-depth.md
 create mode 100644 test/browser-history.spec.ts

diff --git a/.changeset/null-history-state-depth.md b/.changeset/null-history-state-depth.md
new file mode 100644
index 00000000..2570b354
--- /dev/null
+++ b/.changeset/null-history-state-depth.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/router": patch
+---
+
+`browserHistory()` no longer throws when `history.state` is still null after `replaceState` (seen in iOS WKWebView embeds)
diff --git a/src/routers/history.ts b/src/routers/history.ts
index 5a3bde4f..205448b8 100644
--- a/src/routers/history.ts
+++ b/src/routers/history.ts
@@ -16,7 +16,7 @@ export function saveCurrentDepth() {
   if (!window.history.state || window.history.state._depth == null) {
     window.history.replaceState({ ...window.history.state, _depth: window.history.length - 1 }, "");
   }
-  depth = window.history.state._depth;
+  depth = window.history.state?._depth ?? window.history.length - 1;
 }
 
 function keepDepth(state: any) {
diff --git a/test/browser-history.spec.ts b/test/browser-history.spec.ts
new file mode 100644
index 00000000..c49e7987
--- /dev/null
+++ b/test/browser-history.spec.ts
@@ -0,0 +1,13 @@
+import { afterEach, describe, expect, test, vi } from "vitest";
+import { browserHistory } from "../src/index.js";
+
+describe("browserHistory", () => {
+  afterEach(() => vi.restoreAllMocks());
+
+  test("does not throw when replaceState leaves history.state null", () => {
+    vi.spyOn(window.history, "state", "get").mockReturnValue(null);
+    vi.spyOn(window.history, "replaceState").mockImplementation(() => {});
+
+    expect(() => browserHistory()).not.toThrow();
+  });
+});