From d683bc41cc90abcd2c5f064d3f1c2e9a875b09a8 Mon Sep 17 00:00:00 2001
From: Jiachi Liu <inbox@huozhi.im>
Date: Thu, 12 Dec 2024 21:48:23 +0100
Subject: [PATCH] clean up types

---
 packages/next/src/client/components/app-router.tsx    |  2 +-
 .../components/router-reducer/ppr-navigations.ts      | 11 ++++-------
 .../reducers/find-head-in-cache.test.tsx              |  1 +
 .../src/client/components/segment-cache/navigation.ts |  4 ++--
 packages/next/src/server/app-render/types.ts          |  2 +-
 5 files changed, 9 insertions(+), 11 deletions(-)

diff --git a/packages/next/src/client/components/app-router.tsx b/packages/next/src/client/components/app-router.tsx
index fa7b67f837cab..6bcf12ef6cbbe 100644
--- a/packages/next/src/client/components/app-router.tsx
+++ b/packages/next/src/client/components/app-router.tsx
@@ -219,7 +219,7 @@ function Head({
   // If this segment has a `prefetchHead`, it's the statically prefetched data.
   // We should use that on initial render instead of `head`. Then we'll switch
   // to `head` when the dynamic response streams in.
-  const head = headCacheNode !== null ? headCacheNode.head[1] : null
+  const head = headCacheNode !== null ? headCacheNode.head : null
   const prefetchHead =
     headCacheNode !== null ? headCacheNode.prefetchHead : null
 
diff --git a/packages/next/src/client/components/router-reducer/ppr-navigations.ts b/packages/next/src/client/components/router-reducer/ppr-navigations.ts
index b019a41776e3b..1bdcda24dfd47 100644
--- a/packages/next/src/client/components/router-reducer/ppr-navigations.ts
+++ b/packages/next/src/client/components/router-reducer/ppr-navigations.ts
@@ -70,7 +70,7 @@ export function updateCacheNodeOnNavigation(
   oldRouterState: FlightRouterState,
   newRouterState: FlightRouterState,
   prefetchData: CacheNodeSeedData | null,
-  prefetchHead: React.ReactNode | null,
+  prefetchHead: [React.ReactNode | null, React.ReactNode | null],
   isPrefetchHeadPartial: boolean
 ): Task | null {
   // Diff the old and new trees to reuse the shared layouts.
@@ -285,7 +285,7 @@ export function updateCacheNodeOnNavigation(
 function createCacheNodeOnNavigation(
   routerState: FlightRouterState,
   prefetchData: CacheNodeSeedData | null,
-  possiblyPartialPrefetchHead: React.ReactNode | null,
+  possiblyPartialPrefetchHead: [React.ReactNode | null, React.ReactNode | null],
   isPrefetchHeadPartial: boolean
 ): Task {
   // Same traversal as updateCacheNodeNavigation, but we switch to this path
@@ -386,11 +386,7 @@ function createCacheNodeOnNavigation(
       // `prefetchRsc` field.
       rsc,
       prefetchRsc: null,
-      head: [
-        // TODO: change it to support viewport and metadata
-        isLeafSegment ? possiblyPartialPrefetchHead : null,
-        isLeafSegment ? possiblyPartialPrefetchHead : null,
-      ],
+      head: isLeafSegment ? possiblyPartialPrefetchHead : [null, null],
       prefetchHead: null,
       loading,
       parallelRoutes: cacheNodeChildren,
@@ -803,6 +799,7 @@ function finishPendingCacheNode(
   // a pending promise that needs to be resolved with the dynamic head from
   // the server.
   const head = cacheNode.head
+  // Handle head[0] - viewport and head[1] - metadata
   if (isDeferredRsc(head[0])) {
     head[0].resolve(dynamicHead[0])
   }
diff --git a/packages/next/src/client/components/router-reducer/reducers/find-head-in-cache.test.tsx b/packages/next/src/client/components/router-reducer/reducers/find-head-in-cache.test.tsx
index 71dc05f3139da..89707061ca60f 100644
--- a/packages/next/src/client/components/router-reducer/reducers/find-head-in-cache.test.tsx
+++ b/packages/next/src/client/components/router-reducer/reducers/find-head-in-cache.test.tsx
@@ -108,6 +108,7 @@ describe('findHeadInCache', () => {
     expect(result).not.toBeNull()
 
     const [cacheNode, key] = result!
+    expect(cacheNode).toBe(null)
     expect(cacheNode.head[1]).toMatchObject(
       <>
         <title>About page!</title>
diff --git a/packages/next/src/client/components/segment-cache/navigation.ts b/packages/next/src/client/components/segment-cache/navigation.ts
index 7b3ee3417121d..70e8f3445f420 100644
--- a/packages/next/src/client/components/segment-cache/navigation.ts
+++ b/packages/next/src/client/components/segment-cache/navigation.ts
@@ -125,7 +125,7 @@ function navigateUsingPrefetchedRouteTree(
   currentFlightRouterState: FlightRouterState,
   prefetchFlightRouterState: FlightRouterState,
   prefetchSeedData: CacheNodeSeedData | null,
-  prefetchHead: React.ReactNode | null,
+  prefetchHead: [React.ReactNode | null, React.ReactNode | null],
   isPrefetchHeadPartial: boolean,
   canonicalUrl: string
 ): SuccessfulNavigationResult | NoOpNavigationResult {
@@ -307,7 +307,7 @@ async function navigateDynamicallyWithNoPrefetch(
   // In our simulated prefetch payload, we pretend that there's no seed data
   // nor a prefetch head.
   const prefetchSeedData = null
-  const prefetchHead = null
+  const prefetchHead: [null, null] = [null, null]
   const isPrefetchHeadPartial = true
 
   const canonicalUrl = createCanonicalUrl(
diff --git a/packages/next/src/server/app-render/types.ts b/packages/next/src/server/app-render/types.ts
index 9da4daf5eca91..543238d79cd3a 100644
--- a/packages/next/src/server/app-render/types.ts
+++ b/packages/next/src/server/app-render/types.ts
@@ -234,7 +234,7 @@ export type InitialRSCPayload = {
   c: string[]
   /** couldBeIntercepted */
   i: boolean
-  /** initialFlightData: [tree, seedData, [viewport, metadata]] */
+  /** initialFlightData */
   f: FlightDataPath[]
   /** missingSlots */
   m: Set<string> | undefined