refactor: ♻️ mev: handle nil result

Signed-off-by: thanhpp <thanhphanphu18@gmail.com>

pkg/mev/pkg.go

@@ -205,6 +205,24 @@ type SendBundleResult struct {
 	Message           string              `json:"message,omitempty"`
 }
 
+func (r *SendBundleResult) UnmarshalJSON(b []byte) error {
+	if str := string(b); (str == "\"nil\"" || str == "\"null\"") && r != nil {
+		*r = SendBundleResult{}
+		return nil
+	}
+
+	// Otherwise, unmarshal the data as usual
+	// disable this UnmarshalJSON function
+	type Alias SendBundleResult
+	alias := &struct {
+		*Alias
+	}{
+		Alias: (*Alias)(r),
+	}
+
+	return json.Unmarshal(b, &alias)
+}
+
 type SendBundleResults struct {
 	GasUsed int    `json:"gasUsed,omitempty"`
 	TxHash  string `json:"txHash,omitempty"`

pkg/mev/pkg_test.go

@@ -0,0 +1,23 @@
+package mev_test
+
+import (
+	"encoding/json"
+	"testing"
+
+	"github.com/KyberNetwork/tradinglib/pkg/mev"
+	"github.com/test-go/testify/require"
+)
+
+func TestUnmarshalSendBundleResponse1(t *testing.T) {
+	raws := []string{
+		"{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":\"nil\"}",
+		"{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":{}}",
+		"{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":{\"bundleHash\": \"0x0\"}}",
+	}
+
+	for _, raw := range raws {
+		var resp mev.SendBundleResponse
+		require.NoError(t, json.Unmarshal([]byte(raw), &resp))
+		t.Logf("%+v\n", resp)
+	}
+}