fix(InterceptedHistoryApi): Only override pushState and replaceState

src/lib/kernel/InterceptedHistoryApi.svelte.test.ts

@@ -7,15 +7,20 @@ describe('InterceptedHistoryApi', () => {
     const initialUrl = 'http://example.com/';
     let historyApi: InterceptedHistoryApi;
     let browserMocks: ReturnType<typeof setupBrowserMocks>;
+    let origPushState: typeof globalThis.window.history.pushState;
+    let origReplaceState: typeof globalThis.window.history.replaceState;
 
     beforeEach(() => {
         browserMocks = setupBrowserMocks(initialUrl);
+        origPushState = globalThis.window.history.pushState;
+        origReplaceState = globalThis.window.history.replaceState;
         historyApi = new InterceptedHistoryApi();
     });
 
     afterEach(() => {
         historyApi.dispose();
         browserMocks.cleanup();
+        vi.resetAllMocks();
     });
 
     describe('constructor', () => {
@@ -24,9 +29,10 @@ describe('InterceptedHistoryApi', () => {
             expect(historyApi.url.href).toBe(initialUrl);
         });
 
-        test('Should replace window.history with itself.', () => {
+        test("Should replace window.history's pushState and replaceState methods.", () => {
             // Assert.
-            expect(globalThis.window.history).toBe(historyApi);
+            expect(globalThis.window.history.pushState).not.toBe(origPushState);
+            expect(globalThis.window.history.replaceState).not.toBe(origReplaceState);
         });
 
         test('Should use provided initial URL.', () => {
@@ -315,14 +321,13 @@ describe('InterceptedHistoryApi', () => {
 
         test('Should call the original history method when navigation is not cancelled.', () => {
             // Arrange.
-            const originalPushState = vi.spyOn(browserMocks.history, 'pushState');
             const state = { path: { test: 'value' }, hash: {} };
 
             // Act.
             historyApi.pushState(state, '', 'http://example.com/other');
 
             // Assert.
-            expect(originalPushState).toHaveBeenCalledWith(state, '', 'http://example.com/other');
+            expect(origPushState).toHaveBeenCalledWith(state, '', 'http://example.com/other');
         });
     });
 
@@ -375,15 +380,13 @@ describe('InterceptedHistoryApi', () => {
             expect(callback).not.toHaveBeenCalled();
         });
 
-        test('Should restore original window.history.', () => {
-            // Arrange.
-            const originalHistory = browserMocks.history;
-
+        test('Should restore original window.history methods.', () => {
             // Act.
             historyApi.dispose();
 
             // Assert.
-            expect(globalThis.window.history).toBe(originalHistory);
+            expect(globalThis.window.history.pushState).toBe(origPushState);
+            expect(globalThis.window.history.replaceState).toBe(origReplaceState);
         });
 
         test('Should be safe to call multiple times.', () => {
@@ -422,7 +425,6 @@ describe('InterceptedHistoryApi', () => {
             });
             historyApi.on('beforeNavigate', callback1);
             historyApi2.on('beforeNavigate', callback2);
-            expect(globalThis.window.history).toBe(historyApi2);
 
             // Act.
             historyApi2.pushState({}, '', 'http://example.com/test');

src/lib/kernel/InterceptedHistoryApi.svelte.ts

@@ -20,13 +20,16 @@ export class InterceptedHistoryApi extends StockHistoryApi implements FullModeHi
         navigationCancelled: {}
     };
     #nextSubId = 0;
-    #originalHistory: History | undefined;
+    #origReplaceState;
+    #origPushState;
 
     constructor(initialUrl?: string, initialState?: State) {
         super(initialUrl, initialState);
         if (globalThis.window) {
-            this.#originalHistory = globalThis.window.history;
-            globalThis.window.history = this;
+            this.#origReplaceState = globalThis.window.history.replaceState;
+            this.#origPushState = globalThis.window.history.pushState;
+            globalThis.window.history.replaceState = this.replaceState.bind(this);
+            globalThis.window.history.pushState = this.pushState.bind(this);
         }
     }
 
@@ -82,7 +85,7 @@ export class InterceptedHistoryApi extends StockHistoryApi implements FullModeHi
                 );
                 event.state = this.state;
             }
-            this.#originalHistory?.[`${method}State`](event.state, unused, url);
+            (method === 'push' ? this.#origPushState : this.#origReplaceState)?.bind(globalThis.window.history)(event.state, unused, url);
             this.url.href = globalThis.window?.location?.href ?? new URL(url ?? '', this.url).href;
             this.state = event.state as State;
         }
@@ -108,8 +111,9 @@ export class InterceptedHistoryApi extends StockHistoryApi implements FullModeHi
             beforeNavigate: {},
             navigationCancelled: {}
         };
-        if (this.#originalHistory) {
-            globalThis.window.history = this.#originalHistory;
+        if (globalThis.window) {
+            globalThis.window.history.replaceState = this.#origReplaceState!;
+            globalThis.window.history.pushState = this.#origPushState!;
         }
         super.dispose();
     }