diff --git a/src/shared/utils.ts b/src/shared/utils.ts
index 68525600..54a6b12c 100644
--- a/src/shared/utils.ts
+++ b/src/shared/utils.ts
@@ -75,16 +75,16 @@ function isDirFileExists(path: string, type: 'DIR' | 'FILE'): Promise<boolean> {
 }
 
 
-// create directories recursively
-export async function createDir(path: string): Promise<void> {
+/** create directories recursively */
+export async function createDir(path: string): Promise<string> {
   if (! path) {
     throw new Error('value of path param invalid')
   }
   else {
-    path = normalize(path)  // ! required for '.../.myca' under win32
+    const target = normalize(path)  // ! required for '.../.myca' under win32
     /* istanbul ignore else */
-    if (!await isDirExists(path)) {
-      await path.split(sep).reduce(
+    if (!await isDirExists(target)) {
+      await target.split(sep).reduce(
         async (parentDir: Promise<string>, childDir: string) => {
           const curDir = pathResolve(await parentDir, childDir)
 
@@ -94,6 +94,8 @@ export async function createDir(path: string): Promise<void> {
         Promise.resolve(sep),
       )
     }
+
+    return target
   }
 }
 
diff --git a/test/10_shared_utils.test.ts b/test/10_shared_utils.test.ts
index 42a8b6ff..9e26bba2 100644
--- a/test/10_shared_utils.test.ts
+++ b/test/10_shared_utils.test.ts
@@ -73,7 +73,8 @@ describe(filename, () => {
     const randomPath = `${tmpDir}/${pathPrefix}-${random}`
 
     try {
-      await createDir(randomPath)
+      const path = await createDir(randomPath)
+      assert(path === normalize(randomPath))
     }
     catch (ex) {
       return assert(false, ex)
@@ -91,7 +92,8 @@ describe(filename, () => {
     const randomPath = `${tmpDir}/${pathPrefix}-${random}/.test/0ab`
 
     try {
-      await createDir(randomPath)
+      const path = await createDir(randomPath)
+      assert(path === normalize(randomPath))
     }
     catch (ex) {
       return assert(false, ex)