diff --git a/pkg/epubprogress/epubprogress.go b/pkg/epubprogress/epubprogress.go
index 6170dd4..b48b658 100644
--- a/pkg/epubprogress/epubprogress.go
+++ b/pkg/epubprogress/epubprogress.go
@@ -4,6 +4,7 @@ create a progress bar with custom settings.
 package epubprogress
 
 import (
+	"encoding/json"
 	"fmt"
 	"os"
 	"time"
@@ -31,7 +32,10 @@ func New(o Options) epubProgress {
 	}
 
 	if o.Json {
-		return newEpubProgressJson(o)
+		return &epubProgressJson{
+			o: o,
+			e: json.NewEncoder(os.Stdout),
+		}
 	}
 
 	fmtJob := fmt.Sprintf("%%0%dd", len(fmt.Sprint(o.TotalJob)))
diff --git a/pkg/epubprogress/epubprogress_json.go b/pkg/epubprogress/epubprogress_json.go
index 3344958..4b52037 100644
--- a/pkg/epubprogress/epubprogress_json.go
+++ b/pkg/epubprogress/epubprogress_json.go
@@ -2,7 +2,6 @@ package epubprogress
 
 import (
 	"encoding/json"
-	"os"
 )
 
 type epubProgressJson struct {
@@ -11,13 +10,6 @@ type epubProgressJson struct {
 	current int
 }
 
-func newEpubProgressJson(o Options) epubProgress {
-	return &epubProgressJson{
-		o: o,
-		e: json.NewEncoder(os.Stdout),
-	}
-}
-
 func (p *epubProgressJson) Add(num int) error {
 	p.current += num
 	p.e.Encode(map[string]any{