fix/correctly-infer-optional-query-parameters

Author: johannesmartikkala

src/types.ts

@@ -15,6 +15,7 @@ export type OpenapiPaths<Paths> = {
 
 // https://github.com/ajaishankar/openapi-typescript-fetch/issues/71#issuecomment-2847360598
 type NonNever<T> = [T] extends [never | undefined] ? unknown : T
+type IsAny<T> = 0 extends (1 & T) ? true : false;
 
 export type OpArgType<OP> = OP extends {
   parameters?: {
@@ -119,15 +120,21 @@ export type FetchErrorType<F> = F extends TypedFetch<infer OP>
   ? OpErrorType<OP>
   : never
 
-type _CreateFetch<OP, Q = never> = [Q] extends [never]
-  ? () => TypedFetch<OP>
-  : (query: Q) => TypedFetch<OP>
-
 export type CreateFetch<M, OP> = M extends 'post' | 'put' | 'patch' | 'delete'
-  ? OP extends { parameters: { query: infer Q } }
-    ? _CreateFetch<OP, { [K in keyof Q]: true | 1 }>
-    : _CreateFetch<OP>
-  : _CreateFetch<OP>
+  ? OP extends {
+      parameters: {
+        query?: infer Q;
+      };
+    }
+    ? IsAny<Q> extends true
+      ? () => TypedFetch<OP>
+      : [keyof Q] extends [never]
+        ? () => TypedFetch<OP>
+        : {} extends Q
+          ? (query?: { [K in keyof Q]: true | 1 }) => TypedFetch<OP>
+          : (query: { [K in keyof Q]: true | 1 }) => TypedFetch<OP>
+    : () => TypedFetch<OP>
+  : () => TypedFetch<OP>;
 
 export type Middleware = (
   url: string,