Make common.Throw add stacktraces the same as returning an error

js/common/util.go

@@ -17,7 +17,7 @@ func Throw(rt *goja.Runtime, err error) {
 	if e, ok := err.(*goja.Exception); ok { //nolint:errorlint // we don't really want to unwrap here
 		panic(e)
 	}
-	panic(rt.ToValue(err))
+	panic(rt.NewGoError(err)) // this catches the stack unlike rt.ToValue
 }
 
 // GetReader tries to return an io.Reader value from an exported goja value.

js/common/util_test.go

@@ -7,22 +7,21 @@ import (
 
 	"github.com/dop251/goja"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestThrow(t *testing.T) {
 	t.Parallel()
 	rt := goja.New()
 	fn1, ok := goja.AssertFunction(rt.ToValue(func() { Throw(rt, errors.New("aaaa")) }))
-	if assert.True(t, ok, "fn1 is invalid") {
-		_, err := fn1(goja.Undefined())
-		assert.EqualError(t, err, "aaaa")
+	require.True(t, ok, "fn1 is invalid")
+	_, err := fn1(goja.Undefined())
+	assert.EqualError(t, err, "GoError: aaaa")
 
-		fn2, ok := goja.AssertFunction(rt.ToValue(func() { Throw(rt, err) }))
-		if assert.True(t, ok, "fn1 is invalid") {
-			_, err := fn2(goja.Undefined())
-			assert.EqualError(t, err, "aaaa")
-		}
-	}
+	fn2, ok := goja.AssertFunction(rt.ToValue(func() { Throw(rt, err) }))
+	require.True(t, ok, "fn2 is invalid")
+	_, err = fn2(goja.Undefined())
+	assert.EqualError(t, err, "GoError: aaaa")
 }
 
 func TestToBytes(t *testing.T) {

js/eventloop/eventloop_test.go

@@ -211,5 +211,5 @@ func TestEventLoopRejectThrow(t *testing.T) {
 		return err
 	})
 	loop.WaitOnRegistered()
-	require.EqualError(t, err, "Uncaught (in promise) throw error")
+	require.EqualError(t, err, "Uncaught (in promise) GoError: throw error: GoError\n\tat go.k6.io/k6/js/eventloop_test.TestEventLoopRejectThrow.func1 (native)\n\tat <eval>:1:30(1)\n\tat native\n\n")
 }

js/modules/k6/http/file_test.go

@@ -5,7 +5,6 @@ import (
 	"testing"
 
 	"github.com/dop251/goja"
-	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
 
@@ -41,23 +40,24 @@ func TestHTTPFile(t *testing.T) {
 			FileData{Data: input, Filename: "test-ab.bin", ContentType: "application/octet-stream"},
 			"",
 		},
-		{struct{}{}, []string{}, FileData{}, "invalid type struct {}, expected string, []byte or ArrayBuffer"},
+		{struct{}{}, []string{}, FileData{}, "GoError: invalid type struct {}, expected string, []byte or ArrayBuffer"},
 	}
 
 	for _, tc := range testCases {
 		tc := tc
 		t.Run(fmt.Sprintf("%T", tc.input), func(t *testing.T) {
+			cal, _ := goja.AssertFunction(rt.ToValue(mi.file))
+			args := make([]goja.Value, 1, len(tc.args)+1)
+			args[0] = rt.ToValue(tc.input)
+			for _, arg := range tc.args {
+				args = append(args, rt.ToValue(arg))
+			}
+			_, err := cal(goja.Undefined(), args...)
 			if tc.expErr != "" {
-				defer func() {
-					err := recover()
-					require.NotNil(t, err)
-					require.IsType(t, &goja.Object{}, err)
-					val := err.(*goja.Object).Export()
-					require.EqualError(t, val.(error), tc.expErr)
-				}()
+				require.EqualError(t, err, tc.expErr)
+			} else {
+				require.NoError(t, err)
 			}
-			out := mi.file(tc.input, tc.args...)
-			assert.Equal(t, tc.expected, out)
 		})
 	}
 }