diff --git a/editor/formatter.go b/editor/formatter.go
index 220a29e..a8031e0 100644
--- a/editor/formatter.go
+++ b/editor/formatter.go
@@ -19,8 +19,6 @@ import (
 	"net/http"
 	"os"
 	"os/exec"
-	"runtime"
-	"strings"
 
 	"github.com/b3log/wide/conf"
 	"github.com/b3log/wide/session"
@@ -51,8 +49,7 @@ func GoFmtHandler(w http.ResponseWriter, r *http.Request) {
 
 	filePath := args["file"].(string)
 
-	apiPath := runtime.GOROOT() + conf.PathSeparator + "src" + conf.PathSeparator + "pkg"
-	if strings.HasPrefix(filePath, apiPath) { // if it is Go API source code
+	if util.Go.IsAPI(filePath) {
 		// ignore it
 		return
 	}
diff --git a/file/files.go b/file/files.go
index 5066852..4bacb02 100644
--- a/file/files.go
+++ b/file/files.go
@@ -21,7 +21,6 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
-	"runtime"
 	"sort"
 	"strings"
 
@@ -56,10 +55,7 @@ var apiNode *FileNode
 
 // initAPINode builds the Go API file node.
 func initAPINode() {
-	apiPath := runtime.GOROOT() + conf.PathSeparator + "src" + conf.PathSeparator + "pkg" // before Go 1.4
-	if !util.File.IsExist(apiPath) {
-		apiPath = runtime.GOROOT() + conf.PathSeparator + "src" // Go 1.4 and after
-	}
+	apiPath := util.Go.GetAPIPath()
 
 	apiNode = &FileNode{Name: "Go API", Path: apiPath, IconSkin: "ico-ztree-dir-api ", Type: "d",
 		Creatable: false, Removable: false, FileNodes: []*FileNode{}}
diff --git a/util/go.go b/util/go.go
new file mode 100644
index 0000000..79e9ce5
--- /dev/null
+++ b/util/go.go
@@ -0,0 +1,32 @@
+package util
+
+import (
+	"path"
+	"runtime"
+	"strings"
+)
+
+type mygo struct{}
+
+// Go utilities.
+var Go = mygo{}
+
+// GetAPIPath gets the Go source code path.
+//
+//  1. before Go 1.4: $GOROOT/src/pkg
+//  2. Go 1.4 and after: $GOROOT/src
+func (*mygo) GetAPIPath() string {
+	ret := runtime.GOROOT() + "/src/pkg" // before Go 1.4
+	if !File.IsExist(ret) {
+		ret = runtime.GOROOT() + "/src" // Go 1.4 and after
+	}
+
+	return path.Clean(ret)
+}
+
+// IsAPI determines whether the specified path belongs to Go API.
+func (*mygo) IsAPI(path string) bool {
+	apiPath := Go.GetAPIPath()
+
+	return strings.HasPrefix(path, apiPath)
+}