From 58e2d41f60c5fcdc1912911620a4f9eb15129659 Mon Sep 17 00:00:00 2001
From: Tom Heaton <thomas.m.heaton@gmail.com>
Date: Mon, 28 Sep 2026 11:24:40 +0100
Subject: [PATCH] fix: don't throw when history.state is null after
 replaceState

---
 .changeset/null-history-state-depth.md |  5 +++++
 src/lifecycle.ts                       |  2 +-
 test/lifecycle.spec.ts                 | 13 ++++++++++++-
 3 files changed, 18 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/null-history-state-depth.md

diff --git a/.changeset/null-history-state-depth.md b/.changeset/null-history-state-depth.md
new file mode 100644
index 00000000..79256912
--- /dev/null
+++ b/.changeset/null-history-state-depth.md
@@ -0,0 +1,5 @@
+---
+"@solidjs/router": patch
+---
+
+Don't throw on import when `history.state` is still null after `replaceState` (seen in iOS WKWebView embeds)
diff --git a/src/lifecycle.ts b/src/lifecycle.ts
index b1cc15ab..ce8723d4 100644
--- a/src/lifecycle.ts
+++ b/src/lifecycle.ts
@@ -50,7 +50,7 @@ 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;
 }
 if (!isServer) {
   saveCurrentDepth();
diff --git a/test/lifecycle.spec.ts b/test/lifecycle.spec.ts
index b1ef7679..cfad48fb 100644
--- a/test/lifecycle.spec.ts
+++ b/test/lifecycle.spec.ts
@@ -1,5 +1,5 @@
 import { vi } from "vitest";
-import { createBeforeLeave } from "../src/lifecycle.js";
+import { createBeforeLeave, saveCurrentDepth } from "../src/lifecycle.js";
 import type { BeforeLeaveEventArgs, Location } from "../src/types.js";
 
 const mockLocation = { pathname: "/", search: "", hash: "", query: {}, state: null, key: "" } as unknown as Location;
@@ -49,3 +49,14 @@ describe("createBeforeLeave", () => {
     expect(listener).not.toHaveBeenCalled();
   });
 });
+
+describe("saveCurrentDepth", () => {
+  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(() => saveCurrentDepth()).not.toThrow();
+  });
+});