From b7afe5a6af9e2c083f0b331c19cac8aa87f72a03 Mon Sep 17 00:00:00 2001
From: 1911860538 <alxps1911@gmail.com>
Date: Sat, 8 Nov 2025 13:35:02 +0800
Subject: [PATCH 1/2] fix(render): improve JsonpJSON content type handling and
 simplify Context.JSONP

---
 context.go            |  9 +++------
 render/json.go        |  4 +++-
 render/render_test.go | 23 ++++++++++++++++-------
 3 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/context.go b/context.go
index d5ef8b81..918e9330 100644
--- a/context.go
+++ b/context.go
@@ -1135,13 +1135,10 @@ func (c *Context) SecureJSON(code int, obj any) {
 // JSONP serializes the given struct as JSON into the response body.
 // It adds padding to response body to request data from a server residing in a different domain than the client.
 // It also sets the Content-Type as "application/javascript".
+//
+// When the callback parameter is empty, it behaves equivalently to Context.JSON.
 func (c *Context) JSONP(code int, obj any) {
-	callback := c.DefaultQuery("callback", "")
-	if callback == "" {
-		c.Render(code, render.JSON{Data: obj})
-		return
-	}
-	c.Render(code, render.JsonpJSON{Callback: callback, Data: obj})
+	c.Render(code, render.JsonpJSON{Callback: c.Query("callback"), Data: obj})
 }
 
 // JSON serializes the given struct as JSON into the response body.
diff --git a/render/json.go b/render/json.go
index 2f98676c..8f4b144b 100644
--- a/render/json.go
+++ b/render/json.go
@@ -115,17 +115,19 @@ func (r SecureJSON) WriteContentType(w http.ResponseWriter) {
 
 // Render (JsonpJSON) marshals the given interface object and writes it and its callback with custom ContentType.
 func (r JsonpJSON) Render(w http.ResponseWriter) (err error) {
-	r.WriteContentType(w)
 	ret, err := json.API.Marshal(r.Data)
 	if err != nil {
 		return err
 	}
 
 	if r.Callback == "" {
+		writeContentType(w, jsonContentType)
 		_, err = w.Write(ret)
 		return err
 	}
 
+	r.WriteContentType(w)
+
 	callback := template.JSEscapeString(r.Callback)
 	if _, err = w.Write(bytesconv.StringToBytes(callback)); err != nil {
 		return err
diff --git a/render/render_test.go b/render/render_test.go
index d9ae2067..180b0b0c 100644
--- a/render/render_test.go
+++ b/render/render_test.go
@@ -183,19 +183,28 @@ func TestRenderJsonpJSONError(t *testing.T) {
 	assert.Equal(t, `write "`+`);`+`" error`, err.Error())
 }
 
-func TestRenderJsonpJSONError2(t *testing.T) {
+func TestRenderJsonpJSONWithEmptyCallback(t *testing.T) {
 	w := httptest.NewRecorder()
 	data := map[string]any{
 		"foo": "bar",
+		"num": 42,
+		"nested": map[string]any{
+			"key": "value",
+		},
 	}
-	(JsonpJSON{"", data}).WriteContentType(w)
-	assert.Equal(t, "application/javascript; charset=utf-8", w.Header().Get("Content-Type"))
 
-	e := (JsonpJSON{"", data}).Render(w)
-	require.NoError(t, e)
+	err := (JsonpJSON{Callback: "", Data: data}).Render(w)
 
-	assert.JSONEq(t, "{\"foo\":\"bar\"}", w.Body.String())
-	assert.Equal(t, "application/javascript; charset=utf-8", w.Header().Get("Content-Type"))
+	require.NoError(t, err)
+
+	// Verify Content-Type is set to jsonContentType when callback is empty
+	assert.Equal(t, "application/json; charset=utf-8", w.Header().Get("Content-Type"))
+
+	renderData, err := json.API.Marshal(data)
+	require.NoError(t, err)
+
+	// Verify body contains correct JSON data
+	assert.JSONEq(t, string(renderData), w.Body.String())
 }
 
 func TestRenderJsonpJSONFail(t *testing.T) {

From a14cf7c08dc37b7f9308248928aa3b16307f3c2f Mon Sep 17 00:00:00 2001
From: 1911860538 <alxps1911@gmail.com>
Date: Sat, 8 Nov 2025 22:06:23 +0800
Subject: [PATCH 2/2] refactor(render): use WriteJSON when JsonpJson.Callback
 is empty

---
 render/json.go | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/render/json.go b/render/json.go
index 8f4b144b..ceeeca9c 100644
--- a/render/json.go
+++ b/render/json.go
@@ -115,19 +115,17 @@ func (r SecureJSON) WriteContentType(w http.ResponseWriter) {
 
 // Render (JsonpJSON) marshals the given interface object and writes it and its callback with custom ContentType.
 func (r JsonpJSON) Render(w http.ResponseWriter) (err error) {
+	if r.Callback == "" {
+		return WriteJSON(w, r.Data)
+	}
+
+	r.WriteContentType(w)
+
 	ret, err := json.API.Marshal(r.Data)
 	if err != nil {
 		return err
 	}
 
-	if r.Callback == "" {
-		writeContentType(w, jsonContentType)
-		_, err = w.Write(ret)
-		return err
-	}
-
-	r.WriteContentType(w)
-
 	callback := template.JSEscapeString(r.Callback)
 	if _, err = w.Write(bytesconv.StringToBytes(callback)); err != nil {
 		return err