fix(solid-router): implement navigation transitions

e2e/solid-router/basic-file-based/src/routeTree.gen.ts

@@ -21,6 +21,7 @@ import { Route as LayoutRouteImport } from './routes/_layout'
 import { Route as SearchParamsRouteRouteImport } from './routes/search-params/route'
 import { Route as NonNestedRouteRouteImport } from './routes/non-nested/route'
 import { Route as IndexRouteImport } from './routes/index'
+import { Route as TransitionIndexRouteImport } from './routes/transition/index'
 import { Route as SearchParamsIndexRouteImport } from './routes/search-params/index'
 import { Route as RelativeIndexRouteImport } from './routes/relative/index'
 import { Route as RedirectIndexRouteImport } from './routes/redirect/index'
@@ -158,6 +159,11 @@ const IndexRoute = IndexRouteImport.update({
   path: '/',
   getParentRoute: () => rootRouteImport,
 } as any)
+const TransitionIndexRoute = TransitionIndexRouteImport.update({
+  id: '/transition/',
+  path: '/transition/',
+  getParentRoute: () => rootRouteImport,
+} as any)
 const SearchParamsIndexRoute = SearchParamsIndexRouteImport.update({
   id: '/',
   path: '/',
@@ -600,6 +606,7 @@ export interface FileRoutesByFullPath {
   '/redirect': typeof RedirectIndexRoute
   '/relative': typeof RelativeIndexRoute
   '/search-params/': typeof SearchParamsIndexRoute
+  '/transition': typeof TransitionIndexRoute
   '/non-nested/named/$baz': typeof NonNestedNamedBazRouteRouteWithChildren
   '/non-nested/path/baz': typeof NonNestedPathBazRouteRouteWithChildren
   '/non-nested/prefix/prefix{$baz}': typeof NonNestedPrefixPrefixChar123bazChar125RouteRouteWithChildren
@@ -684,6 +691,7 @@ export interface FileRoutesByTo {
   '/redirect': typeof RedirectIndexRoute
   '/relative': typeof RelativeIndexRoute
   '/search-params': typeof SearchParamsIndexRoute
+  '/transition': typeof TransitionIndexRoute
   '/params-ps/named/$foo': typeof ParamsPsNamedFooRouteRouteWithChildren
   '/params-ps/non-nested/$foo': typeof ParamsPsNonNestedFooRouteRouteWithChildren
   '/insidelayout': typeof groupLayoutInsidelayoutRoute
@@ -771,6 +779,7 @@ export interface FileRoutesById {
   '/redirect/': typeof RedirectIndexRoute
   '/relative/': typeof RelativeIndexRoute
   '/search-params/': typeof SearchParamsIndexRoute
+  '/transition/': typeof TransitionIndexRoute
   '/non-nested/named/$baz': typeof NonNestedNamedBazRouteRouteWithChildren
   '/non-nested/path/baz': typeof NonNestedPathBazRouteRouteWithChildren
   '/non-nested/prefix/prefix{$baz}': typeof NonNestedPrefixPrefixChar123bazChar125RouteRouteWithChildren
@@ -860,6 +869,7 @@ export interface FileRouteTypes {
     | '/redirect'
     | '/relative'
     | '/search-params/'
+    | '/transition'
     | '/non-nested/named/$baz'
     | '/non-nested/path/baz'
     | '/non-nested/prefix/prefix{$baz}'
@@ -944,6 +954,7 @@ export interface FileRouteTypes {
     | '/redirect'
     | '/relative'
     | '/search-params'
+    | '/transition'
     | '/params-ps/named/$foo'
     | '/params-ps/non-nested/$foo'
     | '/insidelayout'
@@ -1030,6 +1041,7 @@ export interface FileRouteTypes {
     | '/redirect/'
     | '/relative/'
     | '/search-params/'
+    | '/transition/'
     | '/non-nested/named/$baz'
     | '/non-nested/path/baz'
     | '/non-nested/prefix/prefix{$baz}'
@@ -1112,6 +1124,7 @@ export interface RootRouteChildren {
   ParamsPsIndexRoute: typeof ParamsPsIndexRoute
   RedirectIndexRoute: typeof RedirectIndexRoute
   RelativeIndexRoute: typeof RelativeIndexRoute
+  TransitionIndexRoute: typeof TransitionIndexRoute
   ParamsPsNamedFooRouteRoute: typeof ParamsPsNamedFooRouteRouteWithChildren
   groupSubfolderInsideRoute: typeof groupSubfolderInsideRoute
   ParamsPsNamedPrefixChar123fooChar125Route: typeof ParamsPsNamedPrefixChar123fooChar125Route
@@ -1216,6 +1229,13 @@ declare module '@tanstack/solid-router' {
       preLoaderRoute: typeof IndexRouteImport
       parentRoute: typeof rootRouteImport
     }
+    '/transition/': {
+      id: '/transition/'
+      path: '/transition'
+      fullPath: '/transition'
+      preLoaderRoute: typeof TransitionIndexRouteImport
+      parentRoute: typeof rootRouteImport
+    }
     '/search-params/': {
       id: '/search-params/'
       path: '/'
@@ -2104,6 +2124,7 @@ const rootRouteChildren: RootRouteChildren = {
   ParamsPsIndexRoute: ParamsPsIndexRoute,
   RedirectIndexRoute: RedirectIndexRoute,
   RelativeIndexRoute: RelativeIndexRoute,
+  TransitionIndexRoute: TransitionIndexRoute,
   ParamsPsNamedFooRouteRoute: ParamsPsNamedFooRouteRouteWithChildren,
   groupSubfolderInsideRoute: groupSubfolderInsideRoute,
   ParamsPsNamedPrefixChar123fooChar125Route:

e2e/solid-router/basic-file-based/src/routes/transition/index.tsx

@@ -0,0 +1,48 @@
+import { Link, createFileRoute } from '@tanstack/solid-router'
+import { Suspense, createResource } from 'solid-js'
+import { z } from 'zod'
+
+export const Route = createFileRoute('/transition/')({
+  validateSearch: z.object({
+    n: z.number().default(1),
+  }),
+  component: Home,
+})
+
+function Home() {
+  return (
+    <div class="p-2">
+      <Link
+        data-testid="increase-button"
+        class="border bg-gray-50 px-3 py-1"
+        from="/transition"
+        search={(s) => ({ n: s.n + 1 })}
+      >
+        Increase
+      </Link>
+
+      <Result />
+    </div>
+  )
+}
+
+function Result() {
+  const searchQuery = Route.useSearch()
+
+  const [doubleQuery] = createResource(
+    () => searchQuery().n,
+    async (n) => {
+      await new Promise((r) => setTimeout(r, 1000))
+      return n * 2
+    },
+  )
+
+  return (
+    <div class="mt-2">
+      <Suspense fallback="Loading...">
+        <div data-testid="n-value">n: {searchQuery().n}</div>
+        <div data-testid="double-value">double: {doubleQuery()}</div>
+      </Suspense>
+    </div>
+  )
+}

e2e/solid-router/basic-file-based/tests/transition.spec.ts

@@ -0,0 +1,43 @@
+import { expect, test } from '@playwright/test'
+
+test('transitions should keep old values visible during navigation', async ({
+  page,
+}) => {
+  await page.goto('/transition')
+
+  await expect(page.getByTestId('n-value')).toContainText('n: 1')
+  await expect(page.getByTestId('double-value')).toContainText('double: 2')
+
+  const bodyTexts: Array<string> = []
+
+  const pollInterval = setInterval(async () => {
+    const text = await page
+      .locator('body')
+      .textContent()
+      .catch(() => '')
+    if (text) bodyTexts.push(text)
+  }, 50)
+
+  await page.getByTestId('increase-button').click()
+
+  await page.waitForTimeout(200)
+
+  clearInterval(pollInterval)
+
+  await expect(page.getByTestId('n-value')).toContainText('n: 2', {
+    timeout: 2000,
+  })
+  await expect(page.getByTestId('double-value')).toContainText('double: 4', {
+    timeout: 2000,
+  })
+
+  // With proper transitions, old values should remain visible until new ones arrive
+  const hasLoadingText = bodyTexts.some((text) => text.includes('Loading...'))
+
+  if (hasLoadingText) {
+    throw new Error(
+      'FAILED: "Loading..." appeared during navigation. ' +
+        'Solid Router should use transitions to keep old values visible.',
+    )
+  }
+})

e2e/solid-router/basic-solid-query-file-based/src/routeTree.gen.ts

@@ -12,6 +12,7 @@ import { Route as rootRouteImport } from './routes/__root'
 import { Route as PostsRouteImport } from './routes/posts'
 import { Route as LayoutRouteImport } from './routes/_layout'
 import { Route as IndexRouteImport } from './routes/index'
+import { Route as TransitionIndexRouteImport } from './routes/transition/index'
 import { Route as PostsIndexRouteImport } from './routes/posts.index'
 import { Route as PostsPostIdRouteImport } from './routes/posts.$postId'
 import { Route as LayoutLayout2RouteImport } from './routes/_layout/_layout-2'
@@ -32,6 +33,11 @@ const IndexRoute = IndexRouteImport.update({
   path: '/',
   getParentRoute: () => rootRouteImport,
 } as any)
+const TransitionIndexRoute = TransitionIndexRouteImport.update({
+  id: '/transition/',
+  path: '/transition/',
+  getParentRoute: () => rootRouteImport,
+} as any)
 const PostsIndexRoute = PostsIndexRouteImport.update({
   id: '/',
   path: '/',
@@ -62,13 +68,15 @@ export interface FileRoutesByFullPath {
   '/posts': typeof PostsRouteWithChildren
   '/posts/$postId': typeof PostsPostIdRoute
   '/posts/': typeof PostsIndexRoute
+  '/transition': typeof TransitionIndexRoute
   '/layout-a': typeof LayoutLayout2LayoutARoute
   '/layout-b': typeof LayoutLayout2LayoutBRoute
 }
 export interface FileRoutesByTo {
   '/': typeof IndexRoute
   '/posts/$postId': typeof PostsPostIdRoute
   '/posts': typeof PostsIndexRoute
+  '/transition': typeof TransitionIndexRoute
   '/layout-a': typeof LayoutLayout2LayoutARoute
   '/layout-b': typeof LayoutLayout2LayoutBRoute
 }
@@ -80,6 +88,7 @@ export interface FileRoutesById {
   '/_layout/_layout-2': typeof LayoutLayout2RouteWithChildren
   '/posts/$postId': typeof PostsPostIdRoute
   '/posts/': typeof PostsIndexRoute
+  '/transition/': typeof TransitionIndexRoute
   '/_layout/_layout-2/layout-a': typeof LayoutLayout2LayoutARoute
   '/_layout/_layout-2/layout-b': typeof LayoutLayout2LayoutBRoute
 }
@@ -90,10 +99,17 @@ export interface FileRouteTypes {
     | '/posts'
     | '/posts/$postId'
     | '/posts/'
+    | '/transition'
     | '/layout-a'
     | '/layout-b'
   fileRoutesByTo: FileRoutesByTo
-  to: '/' | '/posts/$postId' | '/posts' | '/layout-a' | '/layout-b'
+  to:
+    | '/'
+    | '/posts/$postId'
+    | '/posts'
+    | '/transition'
+    | '/layout-a'
+    | '/layout-b'
   id:
     | '__root__'
     | '/'
@@ -102,6 +118,7 @@ export interface FileRouteTypes {
     | '/_layout/_layout-2'
     | '/posts/$postId'
     | '/posts/'
+    | '/transition/'
     | '/_layout/_layout-2/layout-a'
     | '/_layout/_layout-2/layout-b'
   fileRoutesById: FileRoutesById
@@ -110,6 +127,7 @@ export interface RootRouteChildren {
   IndexRoute: typeof IndexRoute
   LayoutRoute: typeof LayoutRouteWithChildren
   PostsRoute: typeof PostsRouteWithChildren
+  TransitionIndexRoute: typeof TransitionIndexRoute
 }
 
 declare module '@tanstack/solid-router' {
@@ -135,6 +153,13 @@ declare module '@tanstack/solid-router' {
       preLoaderRoute: typeof IndexRouteImport
       parentRoute: typeof rootRouteImport
     }
+    '/transition/': {
+      id: '/transition/'
+      path: '/transition'
+      fullPath: '/transition'
+      preLoaderRoute: typeof TransitionIndexRouteImport
+      parentRoute: typeof rootRouteImport
+    }
     '/posts/': {
       id: '/posts/'
       path: '/'
@@ -214,6 +239,7 @@ const rootRouteChildren: RootRouteChildren = {
   IndexRoute: IndexRoute,
   LayoutRoute: LayoutRouteWithChildren,
   PostsRoute: PostsRouteWithChildren,
+  TransitionIndexRoute: TransitionIndexRoute,
 }
 export const routeTree = rootRouteImport
   ._addFileChildren(rootRouteChildren)

e2e/solid-router/basic-solid-query-file-based/src/routes/transition/index.tsx

@@ -0,0 +1,55 @@
+import { Link, createFileRoute } from '@tanstack/solid-router'
+import { Suspense, createMemo } from 'solid-js'
+import { queryOptions, useQuery } from '@tanstack/solid-query'
+import { z } from 'zod'
+
+const searchSchema = z.object({
+  n: z.number().default(1),
+})
+
+const doubleQueryOptions = (n: number) =>
+  queryOptions({
+    queryKey: ['transition-double', n],
+    queryFn: async () => {
+      await new Promise((resolve) => setTimeout(resolve, 1000))
+      return n * 2
+    },
+    placeholderData: (oldData) => oldData,
+  })
+
+export const Route = createFileRoute('/transition/')({
+  validateSearch: searchSchema,
+  loader: ({ context: { queryClient }, location }) => {
+    const { n } = searchSchema.parse(location.search)
+    return queryClient.ensureQueryData(doubleQueryOptions(n))
+  },
+  component: TransitionPage,
+})
+
+function TransitionPage() {
+  const search = Route.useSearch()
+
+  const doubleQuery = createMemo(() =>
+    useQuery(() => doubleQueryOptions(search().n)),
+  )
+
+  return (
+    <Suspense fallback="Loading...">
+      <div class="p-2">
+        <Link
+          data-testid="increase-button"
+          class="border bg-gray-50 px-3 py-1"
+          from="/transition"
+          search={(s) => ({ n: s.n + 1 })}
+        >
+          Increase
+        </Link>
+
+        <div class="mt-2">
+          <div data-testid="n-value">n: {search().n}</div>
+          <div data-testid="double-value">double: {doubleQuery().data}</div>
+        </div>
+      </div>
+    </Suspense>
+  )
+}

e2e/solid-router/basic-solid-query-file-based/tests/transition.spec.ts

@@ -0,0 +1,37 @@
+import { expect, test } from '@playwright/test'
+
+test('solid-query transitions keep previous data during navigation', async ({
+  page,
+}) => {
+  await page.goto('/transition')
+
+  await expect(page.getByTestId('n-value')).toContainText('n: 1')
+  await expect(page.getByTestId('double-value')).toContainText('double: 2')
+
+  const bodySnapshots: Array<string> = []
+
+  const interval = setInterval(async () => {
+    const text = await page
+      .locator('body')
+      .textContent()
+      .catch(() => '')
+    if (text) bodySnapshots.push(text)
+  }, 50)
+
+  await page.getByTestId('increase-button').click()
+
+  await page.waitForTimeout(200)
+
+  clearInterval(interval)
+
+  await expect(page.getByTestId('n-value')).toContainText('n: 2', {
+    timeout: 2_000,
+  })
+  await expect(page.getByTestId('double-value')).toContainText('double: 4', {
+    timeout: 2_000,
+  })
+
+  const sawLoading = bodySnapshots.some((text) => text.includes('Loading...'))
+
+  expect(sawLoading).toBeFalsy()
+})

packages/react-router/tests/store-updates-during-navigation.test.tsx

@@ -154,7 +154,7 @@ describe("Store doesn't update *too many* times during navigation", () => {
     // This number should be as small as possible to minimize the amount of work
     // that needs to be done during a navigation.
     // Any change that increases this number should be investigated.
-    expect(updates).toBe(5)
+    expect(updates).toBe(4)
   })
 
   test('sync beforeLoad', async () => {