fix(types): better tuple serialization types (#6616)

Author: pcattori

.changeset/neat-poets-scream.md

@@ -0,0 +1,7 @@
+---
+"remix": patch
+"@remix-run/serve": patch
+"@remix-run/server-runtime": patch
+---
+
+fix(types): better tuple serialization types

packages/remix-server-runtime/serialize.ts

@@ -29,16 +29,16 @@ type Serialize<T> =
   T extends NonJsonPrimitive ? never :
   T extends { toJSON(): infer U } ? U :
   T extends [] ? [] :
-  T extends [unknown, ...unknown[]] ? SerializeTuple<T> :
+  T extends [unknown, ...unknown[]] ? PrettyTransform<T, SerializeTuple<T>> :
   T extends ReadonlyArray<infer U> ? (U extends NonJsonPrimitive ? null : Serialize<U>)[] :
   T extends object ? PrettyTransform<T, SerializeObject<UndefinedToOptional<T>>> :
   never
 ;
 
 /** JSON serialize [tuples](https://www.typescriptlang.org/docs/handbook/2/objects.html#tuple-types) */
-type SerializeTuple<T extends [unknown, ...unknown[]]> = {
-  [k in keyof T]: T[k] extends NonJsonPrimitive ? null : Serialize<T[k]>;
-};
+type SerializeTuple<T extends unknown[]> = T extends [infer F, ...infer R]
+  ? [Serialize<F>, ...SerializeTuple<R>]
+  : [];
 
 /** JSON serialize objects (not including arrays) and classes */
 type SerializeObject<T extends object> = {