Fix BigInt parsing

For an unknown reason BigInt can't be parsed and is being set as a
UnserializableValue. To ensure that we parse it correctly to an int
we need to catch this case when dealing with other UnserializableValue.

common/remote_object.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"fmt"
 	"math"
+	"regexp"
 	"strconv"
 	"strings"
 
@@ -15,6 +16,8 @@ import (
 	"github.com/dop251/goja"
 )
 
+var bigIntR = regexp.MustCompile("^[0-9]*n$")
+
 type objectOverflowError struct{}
 
 // Error returns the description of the overflow error.
@@ -168,6 +171,14 @@ func parseRemoteObject(obj *cdpruntime.RemoteObject) (any, error) {
 		return parseRemoteObjectValue(obj.Type, obj.Subtype, string(obj.Value), obj.Preview)
 	}
 
+	if bigIntR.Match([]byte(obj.UnserializableValue)) {
+		n, err := strconv.ParseInt(strings.ReplaceAll(obj.UnserializableValue.String(), "n", ""), 10, 64)
+		if err != nil {
+			return nil, BigIntParseError{err}
+		}
+		return n, nil
+	}
+
 	switch obj.UnserializableValue.String() {
 	case "-0": // To handle +0 divided by negative number
 		return math.Float64frombits(0 | (1 << 63)), nil

tests/remote_obj_test.go

@@ -156,14 +156,14 @@ func TestEvalRemoteObjectParse(t *testing.T) {
 		{
 			name: "undefined", eval: "undefined", want: goja.Undefined(),
 		},
-		// {
-		// 	// Commented out until fix applied
-		// 	name: "bigint", eval: `BigInt("2")`, want: "2n",
-		// },
-		// {
-		// 	// Commented out until fix applied
-		// 	name: "unwrapped_bigint", eval: "3n", want: "3n",
-		// },
+		{
+			// Commented out until fix applied
+			name: "bigint", eval: `BigInt("2")`, want: 2,
+		},
+		{
+			// Commented out until fix applied
+			name: "unwrapped_bigint", eval: "3n", want: 3,
+		},
 		{
 			name: "float", eval: "3.14", want: 3.14,
 		},