refactor: replace runtime module options with wazero ModuleConfig

README.md

@@ -176,7 +176,7 @@ func main() {
 	// Precompile the script to bytecode
 	byteCode := must(ctx.Compile("script.js", qjs.Code(script), qjs.TypeModule()))
 	// Use a pool of runtimes for concurrent requests
-	pool := qjs.NewPool(3, &qjs.Option{}, func(r *qjs.Runtime) error {
+	pool := qjs.NewPool(3, qjs.Option{}, func(r *qjs.Runtime) error {
 		results := must(r.Context().Eval("script.js", qjs.Bytecode(byteCode), qjs.TypeModule()))
 		// Store the exported functions in the global object for easy access
 		r.Context().Global().SetPropertyStr("handlers", results)
@@ -591,7 +591,7 @@ func main() {
 		return nil
 	}
 	// Create a pool with 3 runtimes
-	pool := qjs.NewPool(3, &qjs.Option{}, setupFunc)
+	pool := qjs.NewPool(3, qjs.Option{}, setupFunc)
 	numWorkers := 5
 	numTasks := 3
 	var wg sync.WaitGroup
@@ -714,15 +714,20 @@ qjs.ToJSValue(ctx, goValue)             // Convert Go value to JS (auto-detects
 
 ```go
 type Option struct {
-    CWD                string  // Working directory
-    MaxStackSize       int     // Stack size limit
-    MemoryLimit        int     // Memory usage limit  
-    MaxExecutionTime   int     // Execution timeout
-    GCThreshold        int     // GC trigger threshold
-    CacheDir           string  // Compilation cache directory
+	ModuleConfig       wazero.ModuleConfig // Wazero module setup (FS, stdio, start functions)
+	MaxStackSize       int                 // Stack size limit
+	MemoryLimit        int                 // Memory usage limit
+	MaxExecutionTime   int                 // Execution timeout
+	GCThreshold        int                 // GC trigger threshold
+	CacheDir           string              // Compilation cache directory
 }
 ```
 
+When `ModuleConfig` is nil, `qjs` creates a default config that mounts the current working
+directory at `/`, enables walltime/nanotime/nanosleep, and wires stdout/stderr to the host.
+When you provide `ModuleConfig` yourself, include `WithStartFunctions()` to clear wazero's
+default `_start` entry unless you explicitly want start functions to run at instantiation.
+
 ## Performance & Security
 
 **Optimization Tips:**

options.go

@@ -3,8 +3,9 @@ package qjs
 import (
 	"context"
 	"fmt"
-	"io"
 	"os"
+
+	"github.com/tetratelabs/wazero"
 )
 
 const (
@@ -31,9 +32,7 @@ const (
 )
 
 type Option struct {
-	CWD               string
-	StartFunctionName string
-	Context           context.Context
+	Context context.Context
 	// Enabling this option significantly increases evaluation time
 	// because every operation must check the done context, which introduces additional overhead.
 	CloseOnContextDone bool
@@ -45,8 +44,7 @@ type Option struct {
 	GCThreshold        int
 	QuickJSWasmBytes   []byte
 	ProxyFunction      any
-	Stdout             io.Writer
-	Stderr             io.Writer
+	ModuleConfig       wazero.ModuleConfig
 }
 
 // EvalOption configures JavaScript evaluation behavior in QuickJS context.
@@ -221,12 +219,6 @@ func getRuntimeOption(registry *ProxyRegistry, options ...Option) (option Option
 		option = options[0]
 	}
 
-	if option.CWD == "" {
-		if option.CWD, err = os.Getwd(); err != nil {
-			return Option{}, fmt.Errorf("cannot get current working directory: %w", err)
-		}
-	}
-
 	if option.Context == nil {
 		option.Context = context.Background()
 	}
@@ -235,12 +227,24 @@ func getRuntimeOption(registry *ProxyRegistry, options ...Option) (option Option
 		option.ProxyFunction = createFuncProxyWithRegistry(registry)
 	}
 
-	if option.Stdout == nil {
-		option.Stdout = os.Stdout
-	}
+	if option.ModuleConfig == nil {
+		var cwd string
+		if cwd, err = os.Getwd(); err != nil {
+			return Option{}, fmt.Errorf("cannot get current working directory: %w", err)
+		}
 
-	if option.Stderr == nil {
-		option.Stderr = os.Stderr
+		fsConfig := wazero.
+			NewFSConfig().
+			WithDirMount(cwd, "/")
+
+		option.ModuleConfig = wazero.NewModuleConfig().
+			WithStartFunctions().
+			WithSysWalltime().
+			WithSysNanotime().
+			WithSysNanosleep().
+			WithFSConfig(fsConfig).
+			WithStdout(os.Stdout).
+			WithStderr(os.Stderr)
 	}
 
 	return option, nil

options_test.go

@@ -8,6 +8,7 @@ import (
 	"github.com/fastschema/qjs"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"github.com/tetratelabs/wazero"
 )
 
 func TestEvalOptions(t *testing.T) {
@@ -22,7 +23,7 @@ func TestEvalOptions(t *testing.T) {
 		val.Free()
 	})
 
-	t.Run("CWDOption", func(t *testing.T) {
+	t.Run("ModuleConfig", func(t *testing.T) {
 		// Store original working directory to restore later
 		originalCwd, err := os.Getwd()
 		require.NoError(t, err)
@@ -31,20 +32,29 @@ func TestEvalOptions(t *testing.T) {
 			_ = os.Chdir(originalCwd)
 		})
 
-		t.Run("default_cwd_from_os_getwd", func(t *testing.T) {
+		t.Run("nil_uses_default_module_config", func(t *testing.T) {
 			runtime, err := qjs.New()
 			require.NoError(t, err)
 			runtime.Close()
 		})
 
-		t.Run("explicit_cwd_provided", func(t *testing.T) {
+		t.Run("custom_fs_mount", func(t *testing.T) {
 			tempDir := t.TempDir()
-			runtime, err := qjs.New(qjs.Option{CWD: tempDir})
+			runtime, err := qjs.New(qjs.Option{
+				ModuleConfig: wazero.NewModuleConfig().
+					WithStartFunctions().
+					WithSysWalltime().
+					WithSysNanotime().
+					WithSysNanosleep().
+					WithFSConfig(wazero.NewFSConfig().WithDirMount(tempDir, "/")).
+					WithStdout(os.Stdout).
+					WithStderr(os.Stderr),
+			})
 			require.NoError(t, err)
 			runtime.Close()
 		})
 
-		t.Run("deleted_working_directory", func(t *testing.T) {
+		t.Run("nil_default_after_deleted_working_directory", func(t *testing.T) {
 			// Create a temporary directory and change to it
 			tempDir := t.TempDir()
 			subDir := filepath.Join(tempDir, "workdir")
@@ -59,10 +69,17 @@ func TestEvalOptions(t *testing.T) {
 			err = os.RemoveAll(subDir)
 			require.NoError(t, err)
 
+			_, getwdErr := os.Getwd()
 			_, err = qjs.New()
 			_ = os.Chdir(originalCwd)
-			assert.Error(t, err)
-			assert.Contains(t, err.Error(), "failed to get runtime options")
+
+			if getwdErr != nil {
+				assert.Error(t, err)
+				assert.Contains(t, err.Error(), "failed to get runtime options")
+				return
+			}
+
+			require.NoError(t, err)
 		})
 	})
 

runtime.go

@@ -132,20 +132,10 @@ func New(options ...Option) (runtime *Runtime, err error) {
 		return nil, fmt.Errorf("failed to setup host module: %w", err)
 	}
 
-	fsConfig := wazero.
-		NewFSConfig().
-		WithDirMount(runtime.option.CWD, "/")
 	if runtime.module, err = runtime.wrt.InstantiateModule(
 		option.Context,
 		compiledQJSModule,
-		wazero.NewModuleConfig().
-			WithStartFunctions(option.StartFunctionName).
-			WithSysWalltime().
-			WithSysNanotime().
-			WithSysNanosleep().
-			WithFSConfig(fsConfig).
-			WithStdout(option.Stdout).
-			WithStderr(option.Stderr),
+		option.ModuleConfig,
 	); err != nil {
 		return nil, fmt.Errorf("failed to instantiate module: %w", err)
 	}

runtime_test.go

@@ -11,6 +11,7 @@ import (
 	"github.com/fastschema/qjs"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
+	"github.com/tetratelabs/wazero"
 )
 
 func testConcurrentRuntimeExecution(t *testing.T, threadID int) {
@@ -165,7 +166,19 @@ func TestRuntime(t *testing.T) {
 
 	t.Run("RuntimeCreationWithErrorStartFunction", func(t *testing.T) {
 		invalidStartFunc := "QJS_Panic"
-		_, err := qjs.New(qjs.Option{StartFunctionName: invalidStartFunc})
+		cwd, getwdErr := os.Getwd()
+		require.NoError(t, getwdErr)
+
+		_, err := qjs.New(qjs.Option{
+			ModuleConfig: wazero.NewModuleConfig().
+				WithStartFunctions(invalidStartFunc).
+				WithSysWalltime().
+				WithSysNanotime().
+				WithSysNanosleep().
+				WithFSConfig(wazero.NewFSConfig().WithDirMount(cwd, "/")).
+				WithStdout(os.Stdout).
+				WithStderr(os.Stderr),
+		})
 		assert.Error(t, err, "Creating runtime with invalid start function should return error")
 	})