[Flight] Use lazy reference for existing modules (#20445)

gaearon · web-flow · commit daf38ecdfcda · 2020-12-11T22:45:18.000Z
diff --git a/packages/react-server/src/ReactFlightServer.js b/packages/react-server/src/ReactFlightServer.js
@@ -435,6 +435,14 @@ export function resolveModelToJSON(
 const writtenModules = request.writtenModules;
 const existingId = writtenModules.get(moduleKey);
 if (existingId !== undefined) {
+ if (parent[0] === REACT_ELEMENT_TYPE && key === '1') {
+ // If we're encoding the "type" of an element, we can refer
+ // to that by a lazy reference instead of directly since React
+ // knows how to deal with lazy values. This lets us suspend
+ // on this component rather than its parent until the code has
+ // loaded.
+ return serializeByRefID(existingId);
+ }
 return serializeByValueID(existingId);
 }
 try {

-Original file line number
+Diff line change
 constwrittenModules=request.writtenModules;
 constexistingId=writtenModules.get(moduleKey);
 if(existingId!==undefined){
 +if(parent[0]===REACT_ELEMENT_TYPE&&key==='1'){
 +// If we're encoding the "type" of an element, we can refer
 +// to that by a lazy reference instead of directly since React
 +// knows how to deal with lazy values. This lets us suspend
 +// on this component rather than its parent until the code has
 +// loaded.
 +returnserializeByRefID(existingId);
 +}
 returnserializeByValueID(existingId);
+}
 try{