From 5f8b55d1dc7042549720e2ec78e436e0cfd147e8 Mon Sep 17 00:00:00 2001
From: "Kwon, Yeong Eon" <eirny.kwon@machbase.com>
Date: Thu, 14 Nov 2024 10:59:14 +0900
Subject: [PATCH] redirect console output

---
 console.go   | 17 +++++++++++++++--
 otto.go      | 14 +++++++++++++-
 otto_test.go | 29 +++++++++++++++++++++++++++++
 runtime.go   |  2 ++
 4 files changed, 59 insertions(+), 3 deletions(-)

diff --git a/console.go b/console.go
index e8d99cf7..8a02a348 100644
--- a/console.go
+++ b/console.go
@@ -2,6 +2,7 @@ package otto
 
 import (
 	"fmt"
+	"io"
 	"os"
 	"strings"
 )
@@ -15,12 +16,24 @@ func formatForConsole(argumentList []Value) string {
 }
 
 func builtinConsoleLog(call FunctionCall) Value {
-	fmt.Fprintln(os.Stdout, formatForConsole(call.ArgumentList)) //nolint:errcheck // Nothing we can do if this fails.
+	var w io.Writer
+	if call.runtime.stdoutWriter != nil {
+		w = call.runtime.stdoutWriter
+	} else {
+		w = os.Stdout
+	}
+	fmt.Fprintln(w, formatForConsole(call.ArgumentList)) //nolint:errcheck // Nothing we can do if this fails.
 	return Value{}
 }
 
 func builtinConsoleError(call FunctionCall) Value {
-	fmt.Fprintln(os.Stdout, formatForConsole(call.ArgumentList)) //nolint:errcheck // Nothing we can do if this fails.
+	var w io.Writer
+	if call.runtime.stdoutWriter != nil {
+		w = call.runtime.stdoutWriter
+	} else {
+		w = os.Stdout
+	}
+	fmt.Fprintln(w, formatForConsole(call.ArgumentList)) //nolint:errcheck // Nothing we can do if this fails.
 	return Value{}
 }
 
diff --git a/otto.go b/otto.go
index 31b7e301..faebe188 100644
--- a/otto.go
+++ b/otto.go
@@ -222,6 +222,7 @@ package otto
 import (
 	"encoding/json"
 	"errors"
+	"io"
 	"strings"
 
 	"github.com/robertkrimen/otto/file"
@@ -238,12 +239,15 @@ type Otto struct {
 }
 
 // New will allocate a new JavaScript runtime.
-func New() *Otto {
+func New(opts ...Option) *Otto {
 	o := &Otto{
 		runtime: newContext(),
 	}
 	o.runtime.otto = o
 	o.runtime.traceLimit = 10
+	for _, opt := range opts {
+		opt(o)
+	}
 	if err := o.Set("console", o.runtime.newConsole()); err != nil {
 		panic(err)
 	}
@@ -775,3 +779,11 @@ func (o Object) MarshalJSON() ([]byte, error) {
 	}
 	return json.Marshal(goValue)
 }
+
+type Option func(*Otto)
+
+func WithStdoutWriter(w io.Writer) Option {
+	return func(o *Otto) {
+		o.runtime.stdoutWriter = w
+	}
+}
diff --git a/otto_test.go b/otto_test.go
index 2ad71569..27557d47 100644
--- a/otto_test.go
+++ b/otto_test.go
@@ -1803,6 +1803,35 @@ func TestOttoInterrupt(t *testing.T) {
 	}
 }
 
+func TestOtterStdoutWriter(t *testing.T) {
+	tests := []struct {
+		name   string
+		script string
+		expect string
+	}{
+		{
+			name:   "console.log",
+			script: "console.log('hello', 'world')",
+			expect: "hello world\n",
+		},
+		{
+			name:   "console.err",
+			script: "console.error('error', 'world')",
+			expect: "error world\n",
+		},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var buf = &bytes.Buffer{}
+			vm := New(WithStdoutWriter(buf))
+			_, err := vm.Run(tc.script)
+			require.NoError(t, err)
+			require.Equal(t, tc.expect, buf.String())
+		})
+	}
+}
+
 func BenchmarkNew(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		New()
diff --git a/runtime.go b/runtime.go
index 70262367..21533e19 100644
--- a/runtime.go
+++ b/runtime.go
@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"io"
 	"math"
 	"path"
 	"reflect"
@@ -66,6 +67,7 @@ type runtime struct {
 	stackLimit   int
 	traceLimit   int
 	lck          sync.Mutex
+	stdoutWriter io.Writer
 }
 
 func (rt *runtime) enterScope(scop *scope) {