This commit implements the onHeadersReady call

packages/react-dom-bindings/src/server/ReactFizzConfigDOMLegacy.js

@@ -12,6 +12,7 @@ import type {
   BoundaryResources,
   StyleQueue,
   Resource,
+  HeadersDescriptor,
 } from './ReactFizzConfigDOM';
 
 import {
@@ -46,6 +47,13 @@ export type RenderState = {
   headChunks: null | Array<Chunk | PrecomputedChunk>,
   externalRuntimeScript: null | any,
   bootstrapChunks: Array<Chunk | PrecomputedChunk>,
+  onHeaders: void | ((headers: HeadersDescriptor) => void),
+  headers: null | {
+    preconnects: string,
+    fontPreloads: string,
+    highImagePreloads: string,
+    remainingCapacity: number,
+  },
   charsetChunks: Array<Chunk | PrecomputedChunk>,
   preconnectChunks: Array<Chunk | PrecomputedChunk>,
   importMapChunks: Array<Chunk | PrecomputedChunk>,
@@ -83,6 +91,7 @@ export function createRenderState(
     undefined,
     undefined,
     undefined,
+    undefined,
   );
   return {
     // Keep this in sync with ReactFizzConfigDOM
@@ -94,6 +103,8 @@ export function createRenderState(
     headChunks: renderState.headChunks,
     externalRuntimeScript: renderState.externalRuntimeScript,
     bootstrapChunks: renderState.bootstrapChunks,
+    onHeaders: renderState.onHeaders,
+    headers: renderState.headers,
     charsetChunks: renderState.charsetChunks,
     preconnectChunks: renderState.preconnectChunks,
     importMapChunks: renderState.importMapChunks,

packages/react-dom/src/server/ReactDOMFizzServerBrowser.js

@@ -48,6 +48,7 @@ type Options = {
   importMap?: ImportMap,
   formState?: ReactFormState<any, any> | null,
   onHeaders?: (headers: Headers) => void,
+  headersLengthHint?: number,
 };
 
 type ResumeOptions = {
@@ -125,6 +126,8 @@ function renderToReadableStream(
         options ? options.bootstrapModules : undefined,
         options ? options.unstable_externalRuntimeSrc : undefined,
         options ? options.importMap : undefined,
+        onHeadersImpl,
+        options ? options.headersLengthHint : undefined,
       ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
@@ -135,7 +138,6 @@ function renderToReadableStream(
       onFatalError,
       options ? options.onPostpone : undefined,
       options ? options.formState : undefined,
-      onHeadersImpl,
     );
     if (options && options.signal) {
       const signal = options.signal;

packages/react-dom/src/server/ReactDOMFizzServerBun.js

@@ -43,6 +43,7 @@ type Options = {
   importMap?: ImportMap,
   formState?: ReactFormState<any, any> | null,
   onHeaders?: (headers: Headers) => void,
+  headersLengthHint?: number,
 };
 
 // TODO: Move to sub-classing ReadableStream.
@@ -113,6 +114,8 @@ function renderToReadableStream(
         options ? options.bootstrapModules : undefined,
         options ? options.unstable_externalRuntimeSrc : undefined,
         options ? options.importMap : undefined,
+        onHeadersImpl,
+        options ? options.headersLengthHint : undefined,
       ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
@@ -123,7 +126,6 @@ function renderToReadableStream(
       onFatalError,
       options ? options.onPostpone : undefined,
       options ? options.formState : undefined,
-      onHeadersImpl,
     );
     if (options && options.signal) {
       const signal = options.signal;

packages/react-dom/src/server/ReactDOMFizzServerEdge.js

@@ -48,6 +48,7 @@ type Options = {
   importMap?: ImportMap,
   formState?: ReactFormState<any, any> | null,
   onHeaders?: (headers: Headers) => void,
+  headersLengthHint?: number,
 };
 
 type ResumeOptions = {
@@ -125,6 +126,8 @@ function renderToReadableStream(
         options ? options.bootstrapModules : undefined,
         options ? options.unstable_externalRuntimeSrc : undefined,
         options ? options.importMap : undefined,
+        onHeadersImpl,
+        options ? options.headersLengthHint : undefined,
       ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
@@ -135,7 +138,6 @@ function renderToReadableStream(
       onFatalError,
       options ? options.onPostpone : undefined,
       options ? options.formState : undefined,
-      onHeadersImpl,
     );
     if (options && options.signal) {
       const signal = options.signal;

packages/react-dom/src/server/ReactDOMFizzServerNode.js

@@ -7,14 +7,13 @@
  * @flow
  */
 
-import type {
-  Request,
-  PostponedState,
-  HeadersDescriptor,
-} from 'react-server/src/ReactFizzServer';
+import type {Request, PostponedState} from 'react-server/src/ReactFizzServer';
 import type {ReactNodeList, ReactFormState} from 'shared/ReactTypes';
 import type {Writable} from 'stream';
-import type {BootstrapScriptDescriptor} from 'react-dom-bindings/src/server/ReactFizzConfigDOM';
+import type {
+  BootstrapScriptDescriptor,
+  HeadersDescriptor,
+} from 'react-dom-bindings/src/server/ReactFizzConfigDOM';
 import type {Destination} from 'react-server/src/ReactServerStreamConfigNode';
 import type {ImportMap} from '../shared/ReactDOMTypes';
 
@@ -65,6 +64,7 @@ type Options = {
   importMap?: ImportMap,
   formState?: ReactFormState<any, any> | null,
   onHeaders?: (headers: HeadersDescriptor) => void,
+  headersLengthHint?: number,
 };
 
 type ResumeOptions = {
@@ -99,6 +99,8 @@ function createRequestImpl(children: ReactNodeList, options: void | Options) {
       options ? options.bootstrapModules : undefined,
       options ? options.unstable_externalRuntimeSrc : undefined,
       options ? options.importMap : undefined,
+      options ? options.onHeaders : undefined,
+      options ? options.headersLengthHint : undefined,
     ),
     createRootFormatContext(options ? options.namespaceURI : undefined),
     options ? options.progressiveChunkSize : undefined,
@@ -109,7 +111,6 @@ function createRequestImpl(children: ReactNodeList, options: void | Options) {
     undefined,
     options ? options.onPostpone : undefined,
     options ? options.formState : undefined,
-    options ? options.onHeaders : undefined,
   );
 }
 

packages/react-dom/src/server/ReactDOMFizzStaticBrowser.js

@@ -45,6 +45,7 @@ type Options = {
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
   importMap?: ImportMap,
   onHeaders?: (headers: Headers) => void,
+  headersLengthHint?: number,
 };
 
 type StaticResult = {
@@ -105,6 +106,8 @@ function prerender(
         options ? options.bootstrapModules : undefined,
         options ? options.unstable_externalRuntimeSrc : undefined,
         options ? options.importMap : undefined,
+        onHeadersImpl,
+        options ? options.headersLengthHint : undefined,
       ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
@@ -114,7 +117,6 @@ function prerender(
       undefined,
       onFatalError,
       options ? options.onPostpone : undefined,
-      onHeadersImpl,
     );
     if (options && options.signal) {
       const signal = options.signal;

packages/react-dom/src/server/ReactDOMFizzStaticEdge.js

@@ -45,6 +45,7 @@ type Options = {
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
   importMap?: ImportMap,
   onHeaders?: (headers: Headers) => void,
+  headersLengthHint?: number,
 };
 
 type StaticResult = {
@@ -104,6 +105,8 @@ function prerender(
         options ? options.bootstrapModules : undefined,
         options ? options.unstable_externalRuntimeSrc : undefined,
         options ? options.importMap : undefined,
+        onHeadersImpl,
+        options ? options.headersLengthHint : undefined,
       ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
@@ -113,7 +116,6 @@ function prerender(
       undefined,
       onFatalError,
       options ? options.onPostpone : undefined,
-      onHeadersImpl,
     );
     if (options && options.signal) {
       const signal = options.signal;

packages/react-dom/src/server/ReactDOMFizzStaticNode.js

@@ -8,11 +8,11 @@
  */
 
 import type {ReactNodeList} from 'shared/ReactTypes';
-import type {BootstrapScriptDescriptor} from 'react-dom-bindings/src/server/ReactFizzConfigDOM';
 import type {
-  PostponedState,
+  BootstrapScriptDescriptor,
   HeadersDescriptor,
-} from 'react-server/src/ReactFizzServer';
+} from 'react-dom-bindings/src/server/ReactFizzConfigDOM';
+import type {PostponedState} from 'react-server/src/ReactFizzServer';
 import type {ImportMap} from '../shared/ReactDOMTypes';
 
 import {Writable, Readable} from 'stream';
@@ -46,6 +46,7 @@ type Options = {
   unstable_externalRuntimeSrc?: string | BootstrapScriptDescriptor,
   importMap?: ImportMap,
   onHeaders?: (headers: HeadersDescriptor) => void,
+  headersLengthHint?: number,
 };
 
 type StaticResult = {
@@ -105,6 +106,8 @@ function prerenderToNodeStream(
         options ? options.bootstrapModules : undefined,
         options ? options.unstable_externalRuntimeSrc : undefined,
         options ? options.importMap : undefined,
+        options ? options.onHeaders : undefined,
+        options ? options.headersLengthHint : undefined,
       ),
       createRootFormatContext(options ? options.namespaceURI : undefined),
       options ? options.progressiveChunkSize : undefined,
@@ -114,7 +117,6 @@ function prerenderToNodeStream(
       undefined,
       onFatalError,
       options ? options.onPostpone : undefined,
-      options ? options.onHeaders : undefined,
     );
     if (options && options.signal) {
       const signal = options.signal;

packages/react-dom/src/shared/ReactDOMTypes.js

@@ -17,7 +17,7 @@ export type PreloadOptions = {
   integrity?: string,
   type?: string,
   nonce?: string,
-  fetchPriority?: 'high' | 'low' | 'auto',
+  fetchPriority?: FetchPriorityEnum,
   imageSrcSet?: string,
   imageSizes?: string,
   referrerPolicy?: string,
@@ -34,7 +34,7 @@ export type PreinitOptions = {
   crossOrigin?: string,
   integrity?: string,
   nonce?: string,
-  fetchPriority?: 'high' | 'low' | 'auto',
+  fetchPriority?: FetchPriorityEnum,
 };
 export type PreinitModuleOptions = {
   as?: string,
@@ -51,7 +51,7 @@ export type PreloadImplOptions = {
   integrity?: ?string,
   nonce?: ?string,
   type?: ?string,
-  fetchPriority?: ?FetchPriorityEnum,
+  fetchPriority?: ?string,
   referrerPolicy?: ?string,
   imageSrcSet?: ?string,
   imageSizes?: ?string,
@@ -65,12 +65,12 @@ export type PreloadModuleImplOptions = {
 export type PreinitStyleOptions = {
   crossOrigin?: ?CrossOriginEnum,
   integrity?: ?string,
-  fetchPriority?: ?FetchPriorityEnum,
+  fetchPriority?: ?string,
 };
 export type PreinitScriptOptions = {
   crossOrigin?: ?CrossOriginEnum,
   integrity?: ?string,
-  fetchPriority?: ?FetchPriorityEnum,
+  fetchPriority?: ?string,
   nonce?: ?string,
 };
 export type PreinitModuleScriptOptions = {