refactor FetchServerResponse shape

packages/next/src/client/components/router-reducer/create-initial-router-state.ts

@@ -102,7 +102,7 @@ export function createInitialRouterState({
     createPrefetchCacheEntryForInitialLoad({
       url,
       kind: PrefetchKind.AUTO,
-      data: [initialFlightData, undefined, couldBeIntercepted],
+      data: { f: initialFlightData, c: undefined, i: !!couldBeIntercepted },
       tree: initialState.tree,
       prefetchCache: initialState.prefetchCache,
       nextUrl: initialState.nextUrl,

packages/next/src/client/components/router-reducer/fetch-server-response.ts

@@ -13,8 +13,8 @@ const { createFromFetch } = (
 
 import type {
   FlightRouterState,
-  FlightData,
   NavigationFlightResponse,
+  FetchServerResponseResult,
 } from '../../../server/app-render/types'
 import {
   NEXT_ROUTER_PREFETCH_HEADER,
@@ -37,12 +37,6 @@ export interface FetchServerResponseOptions {
   readonly isHmrRefresh?: boolean
 }
 
-export type FetchServerResponseResult = [
-  flightData: FlightData,
-  canonicalUrlOverride: URL | undefined,
-  intercepted?: boolean,
-]
-
 function urlToUrlWithoutFlightMarker(url: string): URL {
   const urlWithoutFlightParameters = new URL(url, location.origin)
   urlWithoutFlightParameters.searchParams.delete(NEXT_RSC_UNION_QUERY)
@@ -61,7 +55,11 @@ function urlToUrlWithoutFlightMarker(url: string): URL {
 }
 
 function doMpaNavigation(url: string): FetchServerResponseResult {
-  return [urlToUrlWithoutFlightMarker(url).toString(), undefined, false]
+  return {
+    f: urlToUrlWithoutFlightMarker(url).toString(),
+    c: undefined,
+    i: false,
+  }
 }
 
 /**
@@ -191,7 +189,11 @@ export async function fetchServerResponse(
       return doMpaNavigation(res.url)
     }
 
-    return [response.f, canonicalUrl, interception]
+    return {
+      f: response.f,
+      c: canonicalUrl,
+      i: interception,
+    }
   } catch (err) {
     console.error(
       `Failed to fetch RSC payload for ${url}. Falling back to browser navigation.`,
@@ -200,6 +202,10 @@ export async function fetchServerResponse(
     // If fetch fails handle it like a mpa navigation
     // TODO-APP: Add a test for the case where a CORS request fails, e.g. external url redirect coming from the response.
     // See https://github.com/vercel/next.js/issues/43605#issuecomment-1451617521 for a reproduction.
-    return [url.toString(), undefined, false]
+    return {
+      f: url.toString(),
+      c: undefined,
+      i: false,
+    }
   }
 }

packages/next/src/client/components/router-reducer/ppr-navigations.ts

@@ -3,6 +3,7 @@ import type {
   FlightRouterState,
   FlightSegmentPath,
   Segment,
+  FetchServerResponseResult,
 } from '../../../server/app-render/types'
 import type {
   CacheNode,
@@ -15,7 +16,6 @@ import {
 } from '../../../shared/lib/segment'
 import { matchSegment } from '../match-segments'
 import { createRouterCacheKey } from './create-router-cache-key'
-import type { FetchServerResponseResult } from './fetch-server-response'
 
 // This is yet another tree type that is used to track pending promises that
 // need to be fulfilled once the dynamic data is received. The terminal nodes of
@@ -353,8 +353,7 @@ export function listenForDynamicRequest(
   responsePromise: Promise<FetchServerResponseResult>
 ) {
   responsePromise.then(
-    (response: FetchServerResponseResult) => {
-      const flightData = response[0]
+    ({ f: flightData }: FetchServerResponseResult) => {
       for (const flightDataPath of flightData) {
         const segmentPath = flightDataPath.slice(0, -3)
         const serverRouterState = flightDataPath[flightDataPath.length - 3]

packages/next/src/client/components/router-reducer/prefetch-cache-utils.ts

@@ -1,15 +1,13 @@
 import { createHrefFromUrl } from './create-href-from-url'
-import {
-  fetchServerResponse,
-  type FetchServerResponseResult,
-} from './fetch-server-response'
+import { fetchServerResponse } from './fetch-server-response'
 import {
   PrefetchCacheEntryStatus,
   type PrefetchCacheEntry,
   PrefetchKind,
   type ReadonlyReducerState,
 } from './router-reducer-types'
 import { prefetchQueue } from './reducers/prefetch-reducer'
+import type { FetchServerResponseResult } from '../../../server/app-render/types'
 
 /**
  * Creates a cache key for the router prefetch cache
@@ -152,9 +150,8 @@ export function createPrefetchCacheEntryForInitialLoad({
   kind: PrefetchKind
   data: FetchServerResponseResult
 }) {
-  const [, , intercept] = data
   // if the prefetch corresponds with an interception route, we use the nextUrl to prefix the cache key
-  const prefetchCacheKey = intercept
+  const prefetchCacheKey = data.i
     ? createPrefetchCacheKey(url, nextUrl)
     : createPrefetchCacheKey(url)
 
@@ -204,8 +201,7 @@ function createLazyPrefetchEntry({
       // TODO: `fetchServerResponse` should be more tighly coupled to these prefetch cache operations
       // to avoid drift between this cache key prefixing logic
       // (which is currently directly influenced by the server response)
-      const [, , intercepted] = prefetchResponse
-      if (intercepted) {
+      if (prefetchResponse.i) {
         prefixExistingPrefetchCacheEntry({ url, nextUrl, prefetchCache })
       }
 

packages/next/src/client/components/router-reducer/reducers/hmr-refresh-reducer.ts

@@ -42,7 +42,7 @@ function hmrRefreshReducerImpl(
   })
 
   return cache.lazyData.then(
-    ([flightData, canonicalUrlOverride]) => {
+    ({ f: flightData, c: canonicalUrlOverride }) => {
       // Handle case when navigating to page in `pages` from `app`
       if (typeof flightData === 'string') {
         return handleExternalUrl(

packages/next/src/client/components/router-reducer/reducers/navigate-reducer.ts

@@ -136,7 +136,7 @@ function navigateReducer_noPPR(
   prefetchQueue.bump(data)
 
   return data.then(
-    ([flightData, canonicalUrlOverride]) => {
+    ({ f: flightData, c: canonicalUrlOverride }) => {
       let isFirstRead = false
       // we only want to mark this once
       if (!prefetchValues.lastUsedTime) {
@@ -324,7 +324,7 @@ function navigateReducer_PPR(
   prefetchQueue.bump(data)
 
   return data.then(
-    ([flightData, canonicalUrlOverride]) => {
+    ({ f: flightData, c: canonicalUrlOverride }) => {
       let isFirstRead = false
       // we only want to mark this once
       if (!prefetchValues.lastUsedTime) {

packages/next/src/client/components/router-reducer/reducers/refresh-reducer.ts

@@ -49,7 +49,7 @@ export function refreshReducer(
   })
 
   return cache.lazyData.then(
-    async ([flightData, canonicalUrlOverride]) => {
+    async ({ f: flightData, c: canonicalUrlOverride }) => {
       // Handle case when navigating to page in `pages` from `app`
       if (typeof flightData === 'string') {
         return handleExternalUrl(

packages/next/src/client/components/router-reducer/reducers/server-patch-reducer.ts

@@ -18,8 +18,9 @@ export function serverPatchReducer(
   state: ReadonlyReducerState,
   action: ServerPatchAction
 ): ReducerState {
-  const { serverResponse } = action
-  const [flightData, overrideCanonicalUrl] = serverResponse
+  const {
+    serverResponse: { f: flightData, c: canonicalUrlOverride },
+  } = action
 
   const mutable: Mutable = {}
 
@@ -64,8 +65,8 @@ export function serverPatchReducer(
       )
     }
 
-    const canonicalUrlOverrideHref = overrideCanonicalUrl
-      ? createHrefFromUrl(overrideCanonicalUrl)
+    const canonicalUrlOverrideHref = canonicalUrlOverride
+      ? createHrefFromUrl(canonicalUrlOverride)
       : undefined
 
     if (canonicalUrlOverrideHref) {

packages/next/src/client/components/router-reducer/refetch-inactive-parallel-segments.ts

@@ -71,8 +71,7 @@ async function refreshInactiveParallelSegmentsImpl({
         nextUrl: includeNextUrl ? state.nextUrl : null,
         buildId: state.buildId,
       }
-    ).then((fetchResponse) => {
-      const flightData = fetchResponse[0]
+    ).then(({ f: flightData }) => {
       if (typeof flightData !== 'string') {
         for (const flightDataPath of flightData) {
           // we only pass the new cache as this function is called after clearing the router cache

packages/next/src/client/components/router-reducer/router-reducer-types.ts

@@ -2,8 +2,8 @@ import type { CacheNode } from '../../../shared/lib/app-router-context.shared-ru
 import type {
   FlightRouterState,
   FlightSegmentPath,
+  FetchServerResponseResult,
 } from '../../../server/app-render/types'
-import type { FetchServerResponseResult } from './fetch-server-response'
 
 export const ACTION_REFRESH = 'refresh'
 export const ACTION_NAVIGATE = 'navigate'

packages/next/src/server/app-render/types.ts

@@ -229,6 +229,15 @@ export type ActionFlightResponse = {
   f: FlightData | null
 }
 
+export type FetchServerResponseResult = {
+  /** flightData */
+  f: FlightData
+  /** canonicalUrl */
+  c: URL | undefined
+  /** couldBeIntercepted */
+  i: boolean
+}
+
 export type RSCPayload =
   | InitialRSCPayload
   | NavigationFlightResponse

packages/next/src/shared/lib/app-router-context.shared-runtime.ts

@@ -5,8 +5,10 @@ import type {
   PrefetchKind,
   RouterChangeByServerResponse,
 } from '../../client/components/router-reducer/router-reducer-types'
-import type { FetchServerResponseResult } from '../../client/components/router-reducer/fetch-server-response'
-import type { FlightRouterState } from '../../server/app-render/types'
+import type {
+  FlightRouterState,
+  FetchServerResponseResult,
+} from '../../server/app-render/types'
 import React from 'react'
 
 export type ChildSegmentMap = Map<string, CacheNode>