fix: Maintain location.state in React Router frameworks

packages/docs/content/docs/adapters.mdx

@@ -127,6 +127,14 @@ export function ReactRouter() {
 }
 ```
 
+<Callout>
+
+ Only `BrowserRouter` is supported. There may be support for `HashRouter`
+ in the future (see issue [#810](https://github.com/47ng/nuqs/issues/810)), but
+ support for `MemoryRouter` is not planned.
+
+</Callout>
+
 ## React Router v7
 
 ```tsx title="app/root.tsx"
@@ -151,6 +159,9 @@ export default function App() {
 
   Please pin your imports to the specific version,
   eg: `nuqs/adapters/react-router/v6` or `nuqs/adapters/react-router/v7`.
+
+  The main difference is where the React Router hooks are imported from:
+  `react-router-dom` for v6, and `react-router` for v7.
 </Callout>
 
 ## Testing

packages/e2e/react-router/v6/cypress/e2e/repro-839.cy.ts

@@ -0,0 +1,5 @@
+import { testRepro839LocationStatePersistence } from 'e2e-shared/specs/react-router/repro-839-location-state-persistence.cy'
+
+testRepro839LocationStatePersistence({
+  path: '/repro-839'
+})

packages/e2e/react-router/v6/src/react-router.tsx

@@ -20,6 +20,7 @@ function load(mod: Promise<{ default: any; [otherExports: string]: any }>) {
 const router = createBrowserRouter(
   createRoutesFromElements(
     <Route path="/" element={<RootLayout/>} >,
+      {/* Shared E2E tests */}
       <Route path='hash-preservation'                     lazy={load(import('./routes/hash-preservation'))} />
       <Route path='basic-io/useQueryState'                lazy={load(import('./routes/basic-io.useQueryState'))} />
       <Route path='basic-io/useQueryStates'               lazy={load(import('./routes/basic-io.useQueryStates'))} />
@@ -40,6 +41,8 @@ const router = createBrowserRouter(
       <Route path="form/useQueryStates"                   lazy={load(import('./routes/form.useQueryStates'))} />
       <Route path="referential-stability/useQueryState"   lazy={load(import('./routes/referential-stability.useQueryState'))} />
       <Route path="referential-stability/useQueryStates"  lazy={load(import('./routes/referential-stability.useQueryStates'))} />
+      {/* Reproductions */}
+      <Route path='repro-839'   lazy={load(import('./routes/repro-839'))} />
     </Route>
   ))
 

packages/e2e/react-router/v6/src/routes/repro-839.tsx

@@ -0,0 +1,6 @@
+import { Repro839 } from 'e2e-shared/specs/react-router/repro-839-location-state-persistence'
+import { useLocation, useNavigate } from 'react-router-dom'
+
+export default function Page() {
+  return <Repro839 useLocation={useLocation} useNavigate={useNavigate} />
+}

packages/e2e/react-router/v7/app/routes.ts

@@ -3,6 +3,7 @@ import { type RouteConfig, layout, route } from '@react-router/dev/routes'
 export default [
   // prettier-ignore
   layout('layout.tsx', [
+    // Shared E2E tests
     route('/hash-preservation',                     './routes/hash-preservation.tsx'),
     route('/basic-io/useQueryState',                './routes/basic-io.useQueryState.tsx'),
     route('/basic-io/useQueryStates',               './routes/basic-io.useQueryStates.tsx'),
@@ -22,6 +23,8 @@ export default [
     route('/form/useQueryState',                    './routes/form.useQueryState.tsx'),
     route('/form/useQueryStates',                   './routes/form.useQueryStates.tsx'),
     route('/referential-stability/useQueryState',   './routes/referential-stability.useQueryState.tsx'),
-    route('/referential-stability/useQueryStates',  './routes/referential-stability.useQueryStates.tsx')
+    route('/referential-stability/useQueryStates',  './routes/referential-stability.useQueryStates.tsx'),
+    // Reproductions
+    route('/repro-839',   './routes/repro-839.tsx'),
   ])
 ] satisfies RouteConfig

packages/e2e/react-router/v7/app/routes/repro-839.tsx

@@ -0,0 +1,6 @@
+import { Repro839 } from 'e2e-shared/specs/react-router/repro-839-location-state-persistence'
+import { useLocation, useNavigate } from 'react-router'
+
+export default function Page() {
+  return <Repro839 useLocation={useLocation} useNavigate={useNavigate} />
+}

packages/e2e/react-router/v7/cypress/e2e/repro-839.cy.ts

@@ -0,0 +1,5 @@
+import { testRepro839LocationStatePersistence } from 'e2e-shared/specs/react-router/repro-839-location-state-persistence.cy'
+
+testRepro839LocationStatePersistence({
+  path: '/repro-839'
+})

packages/e2e/remix/app/routes/repro-839.tsx

@@ -0,0 +1,6 @@
+import { useLocation, useNavigate } from '@remix-run/react'
+import { Repro839 } from 'e2e-shared/specs/react-router/repro-839-location-state-persistence'
+
+export default function Page() {
+  return <Repro839 useLocation={useLocation} useNavigate={useNavigate} />
+}

packages/e2e/remix/cypress/e2e/repro-839.cy.ts

@@ -0,0 +1,5 @@
+import { testRepro839LocationStatePersistence } from 'e2e-shared/specs/react-router/repro-839-location-state-persistence.cy'
+
+testRepro839LocationStatePersistence({
+  path: '/repro-839'
+})

packages/e2e/shared/specs/react-router/repro-839-location-state-persistence.cy.ts

@@ -0,0 +1,22 @@
+import { createTest } from '../../create-test'
+
+export const testRepro839LocationStatePersistence = createTest(
+  'Repro for issue #839 - Location state persistence',
+  ({ path }) => {
+    it('persists location.state on shallow URL updates', () => {
+      cy.visit(path)
+      cy.contains('#hydration-marker', 'hydrated').should('be.hidden')
+      cy.get('#setup').click()
+      cy.get('#shallow').click()
+      cy.get('#state').should('have.text', '{"test":"pass"}')
+    })
+
+    it('persists location.state on deep URL updates', () => {
+      cy.visit(path)
+      cy.contains('#hydration-marker', 'hydrated').should('be.hidden')
+      cy.get('#setup').click()
+      cy.get('#deep').click()
+      cy.get('#state').should('have.text', '{"test":"pass"}')
+    })
+  }
+)

packages/e2e/shared/specs/react-router/repro-839-location-state-persistence.tsx

@@ -0,0 +1,34 @@
+import { useQueryState } from 'nuqs'
+
+type Repro839Props = {
+  useNavigate: () => (url: string, options: { state: unknown }) => void
+  useLocation: () => { state: unknown }
+}
+
+export function Repro839({ useNavigate, useLocation }: Repro839Props) {
+  const navigate = useNavigate()
+  const location = useLocation()
+  const [, setShallow] = useQueryState('shallow', {
+    shallow: true
+  })
+  const [, setDeep] = useQueryState('deep', {
+    shallow: false
+  })
+  return (
+    <>
+      <button
+        id="setup"
+        onClick={() => navigate('.', { state: { test: 'pass' } })}
+      >
+        Setup
+      </button>
+      <button id="shallow" onClick={() => setShallow('pass')}>
+        Test shallow
+      </button>
+      <button id="deep" onClick={() => setDeep('pass')}>
+        Test deep
+      </button>
+      <pre id="state">{JSON.stringify(location.state)}</pre>
+    </>
+  )
+}

packages/nuqs/src/adapters/lib/react-router.ts

@@ -16,6 +16,7 @@ type NavigateUrl = {
 type NavigateOptions = {
   replace?: boolean
   preventScrollReset?: boolean
+  state?: unknown
 }
 type NavigateFn = (url: NavigateUrl, options: NavigateOptions) => void
 type UseNavigate = () => NavigateFn
@@ -60,7 +61,8 @@ export function createReactRouterBasedAdapter(
             },
             {
               replace: true,
-              preventScrollReset: true
+              preventScrollReset: true,
+              state: history.state?.usr
             }
           )
         }