more cleanup

internal/functions/registry.go

@@ -67,7 +67,14 @@ func GetFunctionDeclarations() string {
 }
 
 func GetRegisteredFunctions() map[string]Function {
-	return functionRegistry
+	registryMutex.RLock()
+	defer registryMutex.RUnlock()
+
+	result := make(map[string]Function, len(functionRegistry))
+	for k, v := range functionRegistry {
+		result[k] = v
+	}
+	return result
 }
 
 func RegisterFunction[T Args, R any](name string, fn GoFunc[T, R]) {

internal/runtime/runtime.go

@@ -94,11 +94,14 @@ func (r *Runtime) transformCode(tsCode string) ([]byte, error) {
 	})
 
 	if len(result.Errors) > 0 {
-		var allErrs []string
-		for _, e := range result.Errors {
-			allErrs = append(allErrs, e.Text)
+		var b strings.Builder
+		for i, e := range result.Errors {
+			if i > 0 {
+				b.WriteString(", ")
+			}
+			b.WriteString(e.Text)
 		}
-		return nil, fmt.Errorf("transpilation failed: %s", strings.Join(allErrs, ", "))
+		return nil, fmt.Errorf("transpilation failed: %s", b.String())
 	}
 
 	return result.Code, nil
@@ -112,7 +115,7 @@ func callFunc(this *qjs.This, fn functions.Function) (*qjs.Value, error) {
 	for i := range min(len(fnArgs), len(qjsArgs)) {
 		rVal, err := qjs.JsArgToGo(qjsArgs[i], fnArgs[i])
 		if err != nil {
-			panic(err)
+			return nil, fmt.Errorf("argument conversion failed: %w", err)
 		}
 		allArgs = append(allArgs, rVal.Interface())
 	}

internal/stdlib/fetch.go

@@ -31,9 +31,6 @@ type RequestInit struct {
 }
 
 func (o *RequestInit) Validate() error {
-	if o.Method == "" {
-		o.Method = "GET"
-	}
 	return nil
 }
 
@@ -44,35 +41,20 @@ type Response struct {
 	Headers map[string]string `json:"headers"`
 }
 
-type AddArgs struct {
-	A int `json:"a"`
-	B int `json:"b"`
-}
-
-func (a AddArgs) Validate() error {
-	return nil
-}
-
-type GreetArgs struct {
-	Name string `json:"name"`
-}
-
-func (g GreetArgs) Validate() error {
-	return nil
-}
-
-func Fetch(_ context.Context, args FetchArgs) (Response, error) {
+func Fetch(ctx context.Context, args FetchArgs) (Response, error) {
 	method := "GET"
 	headers := make(map[string]string)
 
 	if args.Init != nil {
-		method = args.Init.Method
+		if args.Init.Method != "" {
+			method = args.Init.Method
+		}
 		if args.Init.Headers != nil {
 			maps.Copy(headers, args.Init.Headers)
 		}
 	}
 
-	req, err := http.NewRequest(method, args.Input, nil)
+	req, err := http.NewRequestWithContext(ctx, method, args.Input, nil)
 	if err != nil {
 		return Response{}, fmt.Errorf("failed to create request: %w", err)
 	}