feat: enhance $Infer handling for schemas, update type resolution logic

Author: himself65

packages/better-call/src/endpoint.test.ts

@@ -218,6 +218,28 @@ describe("types", async () => {
 				}>();
 			},
 		);
+
+		// $Infer.body accepts a StandardSchemaV1 schema directly and resolves
+		// its output type instead of leaking the schema's internal structure.
+		const bodySchema = z.object({ name: z.string(), age: z.number() });
+		createEndpoint(
+			"/path",
+			{
+				method: "POST",
+				body: {},
+				metadata: {
+					$Infer: {
+						body: bodySchema,
+					},
+				},
+			},
+			async (c) => {
+				expectTypeOf(c.body).toEqualTypeOf<{
+					name: string;
+					age: number;
+				}>();
+			},
+		);
 	});
 
 	it("query", async () => {
@@ -281,6 +303,27 @@ describe("types", async () => {
 				}>();
 			},
 		);
+
+		// $Infer.query accepts a StandardSchemaV1 schema directly and resolves
+		// its output type instead of leaking the schema's internal structure.
+		const querySchema = z.object({ page: z.number(), limit: z.number() });
+		createEndpoint(
+			"/path",
+			{
+				method: "GET",
+				metadata: {
+					$Infer: {
+						query: querySchema,
+					},
+				},
+			},
+			async (c) => {
+				expectTypeOf(c.query).toEqualTypeOf<{
+					page: number;
+					limit: number;
+				}>();
+			},
+		);
 	});
 
 	it("params", async () => {

packages/better-call/src/types.ts

@@ -17,13 +17,24 @@ export type HTTPMethod = "GET" | "POST" | "PUT" | "DELETE" | "PATCH" | "HEAD";
 export type ResolveMethod<M> =
 	M extends Array<infer U> ? U : M extends "*" ? HTTPMethod : M;
 
+/**
+ * Resolve a $Infer value: if it's a StandardSchemaV1 schema, extract the
+ * output type; otherwise use as-is.
+ */
+type ResolveInferValue<T> = T extends StandardSchemaV1
+	? StandardSchemaV1.InferOutput<T>
+	: T;
+type ResolveInferValueInput<T> = T extends StandardSchemaV1
+	? StandardSchemaV1.InferInput<T>
+	: T;
+
 /**
  * Resolves a body schema to its output type.
  */
 export type ResolveBody<S, Meta = undefined> = Meta extends {
 	$Infer: { body: infer B };
 }
-	? B
+	? ResolveInferValue<B>
 	: S extends StandardSchemaV1
 		? StandardSchemaV1.InferOutput<S>
 		: any;
@@ -34,7 +45,7 @@ export type ResolveBody<S, Meta = undefined> = Meta extends {
 export type ResolveQuery<S, Meta = undefined> = Meta extends {
 	$Infer: { query: infer Q };
 }
-	? Q
+	? ResolveInferValue<Q>
 	: S extends StandardSchemaV1
 		? StandardSchemaV1.InferOutput<S>
 		: Record<string, any> | undefined;
@@ -45,7 +56,7 @@ export type ResolveQuery<S, Meta = undefined> = Meta extends {
 export type ResolveBodyInput<S, Meta = undefined> = Meta extends {
 	$Infer: { body: infer B };
 }
-	? B
+	? ResolveInferValueInput<B>
 	: S extends StandardSchemaV1
 		? StandardSchemaV1.InferInput<S>
 		: undefined;
@@ -56,7 +67,7 @@ export type ResolveBodyInput<S, Meta = undefined> = Meta extends {
 export type ResolveQueryInput<S, Meta = undefined> = Meta extends {
 	$Infer: { query: infer Q };
 }
-	? Q
+	? ResolveInferValueInput<Q>
 	: S extends StandardSchemaV1
 		? StandardSchemaV1.InferInput<S>
 		: Record<string, any> | undefined;
@@ -67,7 +78,7 @@ export type ResolveQueryInput<S, Meta = undefined> = Meta extends {
 export type ResolveErrorInput<S, Meta = undefined> = Meta extends {
 	$Infer: { error: infer E };
 }
-	? E
+	? ResolveInferValueInput<E>
 	: S extends StandardSchemaV1
 		? StandardSchemaV1.InferInput<S>
 		: undefined;