fix(history): correctly handle history state in createMemoryHistory

packages/history/src/index.ts

@@ -366,38 +366,34 @@ export function createMemoryHistory(
 ): RouterHistory {
   const entries = opts.initialEntries
   let index = opts.initialIndex ?? entries.length - 1
-  let currentState = {
-    key: createRandomKey(),
-  } as HistoryState
+  const states = entries.map(() => ({}) as HistoryState)
 
-  const getLocation = () => parseHref(entries[index]!, currentState)
+  const getLocation = () => parseHref(entries[index]!, states[index])
 
   return createHistory({
     getLocation,
     getLength: () => entries.length,
     pushState: (path, state) => {
-      currentState = state
       // Removes all subsequent entries after the current index to start a new branch
       if (index < entries.length - 1) {
         entries.splice(index + 1)
+        states.splice(index + 1)
       }
+      states.push(state)
       entries.push(path)
       index = Math.max(entries.length - 1, 0)
     },
     replaceState: (path, state) => {
-      currentState = state
+      states[index] = state
       entries[index] = path
     },
     back: () => {
-      currentState = assignKey(currentState)
       index = Math.max(index - 1, 0)
     },
     forward: () => {
-      currentState = assignKey(currentState)
       index = Math.min(index + 1, entries.length - 1)
     },
     go: (n) => {
-      currentState = assignKey(currentState)
       index = Math.min(Math.max(index + n, 0), entries.length - 1)
     },
     createHref: (path) => path,

packages/history/tests/createMemoryHistory.test.ts

@@ -64,4 +64,16 @@ describe('createMemoryHistory', () => {
     history.push('/c')
     expect(history.length).toBe(2)
   })
+
+  test('state', () => {
+    const history = createMemoryHistory()
+    history.push('/a', { i: 1 })
+    expect((history.location.state as any).i).toBe(1)
+    history.replace('/b', { i: 2 })
+    expect((history.location.state as any).i).toBe(2)
+    history.back()
+    expect((history.location.state as any).i).toBeUndefined()
+    history.push('/c', { i: 3 })
+    expect((history.location.state as any).i).toBe(3)
+  })
 })