diff --git a/sjson/dec.go b/cjson/dec.go
similarity index 86%
rename from sjson/dec.go
rename to cjson/dec.go
index 269da02..84d4d2e 100644
--- a/sjson/dec.go
+++ b/cjson/dec.go
@@ -1,4 +1,4 @@
-package sjson
+package cjson
 
 import "github.com/d5/tengo/v2"
 import "encoding/json"
@@ -28,18 +28,20 @@ func NewDecoder(args ...tengo.Object) (tengo.Object, error) {
 		inputName = StrStdin
 	} else if len(args) > 1 {
 		return nil, tengo.ErrWrongNumArguments
-	}
-
-	inputObject := args[0]
-	inputName, ok := tengo.ToString(inputObject)
-	if !ok {
-		return nil, tengo.ErrInvalidArgumentType{
-			Name: "first",
-			Expected: "stringer",
-			Found: inputObject.TypeName(),
+	} else {
+		var ok bool
+		inputObject := args[0]
+		inputName, ok = tengo.ToString(inputObject)
+		if !ok {
+			return nil, tengo.ErrInvalidArgumentType{
+				Name: "first",
+				Expected: "stringer",
+				Found: inputObject.TypeName(),
+			}
 		}
 	}
 
+
 	var reader io.Reader
 	var err error
 	switch {
diff --git a/sjson/sjson.go b/cjson/main.go
similarity index 97%
rename from sjson/sjson.go
rename to cjson/main.go
index f53e04c..8c16261 100644
--- a/sjson/sjson.go
+++ b/cjson/main.go
@@ -1,4 +1,4 @@
-package sjson
+package cjson
 
 import "github.com/d5/tengo/v2"
 import "io"
diff --git a/tests/cjson.xgo b/tests/cjson.xgo
new file mode 100644
index 0000000..0af89fa
--- /dev/null
+++ b/tests/cjson.xgo
@@ -0,0 +1,16 @@
+cjson := import("cjson")
+fmt := import("fmt")
+fmt.println(cjson.__check())
+
+dec := cjson.new_decoder("tests/data.cjson")
+
+for {
+	v := dec.decode()
+	if is_error(v) {
+		break
+	}
+	if !v {
+		break
+	}
+	fmt.println(v)
+}
diff --git a/tests/data.cjson b/tests/data.cjson
new file mode 100644
index 0000000..187ebe4
--- /dev/null
+++ b/tests/data.cjson
@@ -0,0 +1,4 @@
+{"somename": {
+	"value": 1
+}}
+["array",135,"integers", 135, 135]
diff --git a/tests/sjson.xgo b/tests/sjson.xgo
deleted file mode 100644
index cc499c3..0000000
--- a/tests/sjson.xgo
+++ /dev/null
@@ -1,13 +0,0 @@
-sjson := import("sjson")
-fmt := import("fmt")
-fmt.println(sjson.__check())
-
-dec := sjson.new_decoder("<stdin>")
-
-for {
-	v := dec.decode()
-	if !v {
-		break
-	}
-	fmt.println(v)
-}
diff --git a/xtool/main.go b/xtool/main.go
index 461b688..498f404 100644
--- a/xtool/main.go
+++ b/xtool/main.go
@@ -19,7 +19,7 @@ import (
 )
 
 import "surdeus.su/core/cli/mtool"
-import "surdeus.su/core/xgo/sjson"
+import "surdeus.su/core/xgo/cjson"
 
 const (
 	sourceFileExt = ".xgo"
@@ -53,7 +53,7 @@ func Run(flags *mtool.Flags) {
 		return
 	}
 	modules := stdlib.GetModuleMap(stdlib.AllModuleNames()...)
-	modules.AddBuiltinModule("sjson", sjson.Module)
+	modules.AddBuiltinModule("cjson", cjson.Module)
 	if len(iargs) == 0 {
 		// REPL
 		RunREPL(modules, os.Stdin, os.Stdout)