allow func(...) (err) back

generator.go

@@ -4,7 +4,6 @@ import (
 	_ "embed"
 	"errors"
 	"fmt"
-	"log"
 	"os"
 	"reflect"
 	"slices"
@@ -25,7 +24,6 @@ func GenClient(api any, outPutPath string) error {
 	if err := os.WriteFile(outPutPath, []byte(ts), 0644); err != nil {
 		return err
 	}
-	log.Println("Generated TS client", outPutPath)
 	return nil
 }
 
@@ -46,16 +44,33 @@ func GenerateTS(apiType reflect.Type, clientName string) (string, error) {
 			if i == 0 {
 				continue
 			}
-			log.Println(param)
 			collectStructs(param, structs)
 		}
 
 		outParams := method.Type.NumOut()
 
-		if outParams > 1 && method.Type.Out(1).Implements(errorType) {
+		unsupportedMethod := "not supported, allowed layout are \nfunc() (error) \nfunc() (struct, error), \nfunc(x...) (struct, error)"
+		//func()
+		if outParams == 0 {
+			return "", errors.New(method.Name + unsupportedMethod)
+		}
+
+		//func() (err)
+		if outParams == 1 {
+			if method.Type.Out(0).Implements(errorType) {
 				collectStructs(method.Type.Out(0), structs)
 			} else {
-			return "", errors.New("supported layout are func() (Struct, error), func(x...) (*Struct, error) ")
+				return "", errors.New(method.Name + unsupportedMethod)
+			}
+		}
+
+		//func() (struct, err)
+		if outParams > 1 && method.Type.Out(1).Implements(errorType) {
+			collectStructs(method.Type.Out(0), structs)
+		}
+
+		if outParams > 2 {
+			return "", errors.New(method.Name + unsupportedMethod)
 		}
 
 	}
@@ -97,46 +112,39 @@ func GenerateTS(apiType reflect.Type, clientName string) (string, error) {
 	b.WriteString(fmt.Sprintf("export interface %s {\n", clientName))
 	for m := range apiType.Methods() {
 		params := []string{}
-		i := -1
+
-		for ptypeGo := range m.Type.Ins() {
+		tsParamIdx := 0
-			i++
+		for i := 0; i < m.Type.NumIn(); i++ {
-			//skip self or context
+			ptypeGo := m.Type.In(i)
-			if ptypeGo.String() == "context.Context" || i == 0 {
+
+			if i == 0 {
+				continue
+			}
+			if ptypeGo.Implements(reflect.TypeOf((*interface{ Done() <-chan struct{} })(nil)).Elem()) ||
+				strings.Contains(ptypeGo.String(), "context.Context") {
 				continue
 			}
 
 			var pname string
-			if ptypeGo.Kind() == reflect.Struct {
+			if ptypeGo.Kind() == reflect.Struct && ptypeGo.Name() != "" {
-				named := false
-				for fields := range ptypeGo.Fields() {
-					tag := fields.Tag.Get("json")
-					if tag != "" && tag != "-" {
-						pname = tag
-						named = true
-						break
-					}
-				}
-				if !named {
-					// fallback to camelCase struct name
-					if ptypeGo.Name() != "" {
 				pname = strings.ToLower(ptypeGo.Name()[:1]) + ptypeGo.Name()[1:]
 			} else {
-						pname = fmt.Sprintf("arg%d", i-1)
+				pname = fmt.Sprintf("arg%d", tsParamIdx)
-					}
-				}
-			} else {
-				pname = fmt.Sprintf("arg%d", i-1)
 			}
 
 			ptype := goTypeToTS(ptypeGo)
-
 			params = append(params, fmt.Sprintf("%s: %s", pname, ptype))
+			tsParamIdx++
 		}
 
 		resType := "any"
 		if m.Type.NumOut() > 0 {
 			resType = goTypeToTS(m.Type.Out(0))
+			if m.Type.Out(0).Implements(errorType) {
+				resType = "any" // It's just a func() error
 			}
+		}
+
 		b.WriteString(fmt.Sprintf("  %s(%s): Promise<RPCResult<%s>>;\n", m.Name, strings.Join(params, ", "), resType))
 	}
 	b.WriteString("}\n\n")

generator_test.go

@@ -0,0 +1,141 @@
+package rpc
+
+import (
+	"os"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+type User struct {
+	ID       int    `json:"id"`
+	Username string `json:"username"`
+	IsActive bool   `json:"is_active"`
+	PtrField *int   `json:"ptr_field"`
+}
+
+type Order struct {
+	OrderID int    `json:"order_id"`
+	Items   []Item `json:"items"`
+}
+
+type Item struct {
+	Name string `json:"name"`
+}
+
+type MockAPI struct{}
+
+func (s *MockAPI) GetUser(id int) (User, error) { return User{}, nil }
+func (s *MockAPI) CreateOrder(o Order) error    { return nil }
+func (s *MockAPI) NoArgs() error                { return nil }
+
+func TestGoTypeToTS(t *testing.T) {
+	tests := []struct {
+		name     string
+		input    any
+		expected string
+	}{
+		{"Int", 42, "number"},
+		{"String", "hello", "string"},
+		{"Bool", true, "boolean"},
+		{"Slice", []string{}, "string[]"},
+		{"Byte Slice", []byte{}, "string"},
+		{"Pointer", new(int), "number"},
+		{"Map", map[string]int{}, "{ [key: string]: number }"},
+		{"Struct", User{}, "User"},
+		{"Anon Struct", struct {
+			Name string `json:"name"`
+		}{Name: "test"}, "{ name: string }"},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			typ := reflect.TypeOf(tt.input)
+			got := goTypeToTS(typ)
+			if got != tt.expected {
+				t.Errorf("goTypeToTS() = %v, want %v", got, tt.expected)
+			}
+		})
+	}
+}
+
+func TestCollectStructs(t *testing.T) {
+	structs := make(map[string]reflect.Type)
+
+	// Test nested collection
+	collectStructs(reflect.TypeOf(Order{}), structs)
+
+	if _, ok := structs["Order"]; !ok {
+		t.Error("Expected Order in map")
+	}
+	if _, ok := structs["Item"]; !ok {
+		t.Error("Expected Item (nested) in map")
+	}
+}
+
+func TestGenerateTS_Success(t *testing.T) {
+	api := &MockAPI{}
+	output, err := GenerateTS(reflect.TypeOf(api), "TestClient")
+	if err != nil {
+		t.Fatalf("GenerateTS failed: %v", err)
+	}
+
+	expectedStrings := []string{
+		"export interface User {",
+		"id: number;",
+		"is_active: boolean;",
+		"export interface TestClient {",
+		"GetUser(arg0: number): Promise<RPCResult<User>>;",
+		"CreateOrder(order: Order): Promise<RPCResult<any>>;",
+		"useBackend(url: string = '/ws')",
+	}
+
+	for _, s := range expectedStrings {
+		if !strings.Contains(output, s) {
+			t.Errorf("Generated TS missing expected string: %s", s)
+		}
+	}
+}
+
+type APIWithTooManyReturns struct{}
+
+func (s *APIWithTooManyReturns) Bad(id int) (int, int, error) { return 0, 0, nil }
+
+type APIWithNoErrorHandler struct{}
+
+func (s *APIWithNoErrorHandler) Bad(id int) int { return 0 }
+
+func TestGenerateTS_Validation(t *testing.T) {
+	type BadAPI struct{}
+
+	t.Run("InvalidReturnCount", func(t *testing.T) {
+		api := &APIWithTooManyReturns{}
+		_, err := GenerateTS(reflect.TypeOf(api), "Client")
+		if err == nil {
+			t.Error("Expected error for method with 3 return values")
+		}
+	})
+
+	t.Run("NoResidentError", func(t *testing.T) {
+		api := &APIWithNoErrorHandler{}
+		_, err := GenerateTS(reflect.TypeOf(api), "Client")
+		if err == nil {
+			t.Error("Expected error for method missing 'error' return type")
+		}
+	})
+}
+
+func TestGenClient(t *testing.T) {
+	tmpFile := "test_client.ts"
+	defer os.Remove(tmpFile)
+
+	api := &MockAPI{}
+	err := GenClient(api, tmpFile)
+	if err != nil {
+		t.Fatalf("GenClient failed: %v", err)
+	}
+
+	if _, err := os.Stat(tmpFile); os.IsNotExist(err) {
+		t.Error("GenClient did not create the file")
+	}
+}