feat(client): add a convenient param.SetJSON helper

Author: stainless-app[bot]

packages/param/param.go

@@ -41,6 +41,19 @@ func Override[T ParamStruct, PtrT InferPtr[T]](v any) T {
 	return *pt
 }
 
+// SetJSON configures a param struct to serialize with the provided raw JSON data.
+// Use this when you have existing JSON that you want to send as request parameters.
+//
+//	var req example.NewUserParams
+//	var rawJSON = []byte(`{"name": "...", "age": 40}`)
+//	param.SetJSON(rawJSON, &req)
+//	res, err := client.Users.New(ctx, req)
+//
+// Note: The struct's existing fields will be ignored; only the provided JSON is serialized.
+func SetJSON(rawJSON []byte, ptr anyParamStruct) {
+	ptr.setMetadata(json.RawMessage(rawJSON))
+}
+
 // IsOmitted returns true if v is the zero value of its type.
 //
 // If IsOmitted is true, and the field uses a `json:"...,omitzero"` tag,
@@ -91,6 +104,11 @@ type ParamStruct interface {
 	extraFields() map[string]any
 }
 
+// A pointer to ParamStruct
+type anyParamStruct interface {
+	setMetadata(any)
+}
+
 // This is an implementation detail and should never be explicitly set.
 type InferPtr[T ParamStruct] interface {
 	setMetadata(any)