diff --git a/packages/react-dom-bindings/src/server/ReactDOMServerLegacyFormatConfig.js b/packages/react-dom-bindings/src/server/ReactDOMServerLegacyFormatConfig.js
index 84dd47e706f94..cfc0d3140c435 100644
--- a/packages/react-dom-bindings/src/server/ReactDOMServerLegacyFormatConfig.js
+++ b/packages/react-dom-bindings/src/server/ReactDOMServerLegacyFormatConfig.js
@@ -44,6 +44,8 @@ export type ResponseState = {
   requiresEmbedding: boolean,
   rendered: DocumentStructureTag,
   flushed: DocumentStructureTag,
+  charsetChunks: Array<Chunk | PrecomputedChunk>,
+  hoistableChunks: Array<Chunk | PrecomputedChunk>,
   placeholderPrefix: PrecomputedChunk,
   segmentPrefix: PrecomputedChunk,
   boundaryPrefix: string,
@@ -87,6 +89,8 @@ export function createResponseState(
     requiresEmbedding: false,
     rendered: NONE,
     flushed: NONE,
+    charsetChunks: [],
+    hoistableChunks: [],
     placeholderPrefix: responseState.placeholderPrefix,
     segmentPrefix: responseState.segmentPrefix,
     boundaryPrefix: responseState.boundaryPrefix,