diff --git a/src/area/README.md b/src/area/README.md
index e96be9c99..1583a0e12 100644
--- a/src/area/README.md
+++ b/src/area/README.md
@@ -124,7 +124,7 @@ export default {
 };
 ```
 
-All code of China: [Area.json](https://github.com/youzan/vant/blob/dev/src/area/demo/area-en.js)
+All code of China: [Area.json](https://github.com/youzan/vant/blob/dev/src/area/demo/area-en.ts)
 
 ### argument of callback function confirm
 
diff --git a/src/area/README.zh-CN.md b/src/area/README.zh-CN.md
index bf54b2bbe..50563d7af 100644
--- a/src/area/README.zh-CN.md
+++ b/src/area/README.zh-CN.md
@@ -131,7 +131,7 @@ export default {
 };
 ```
 
-完整数据见 [Area.json](https://github.com/youzan/vant/blob/dev/src/area/demo/area.js)
+完整数据见 [Area.json](https://github.com/youzan/vant/blob/dev/src/area/demo/area.ts)
 
 ### 点击完成时返回的数据格式
 
diff --git a/src/area/demo/area-en.js b/src/area/demo/area-en.ts
similarity index 100%
rename from src/area/demo/area-en.js
rename to src/area/demo/area-en.ts
diff --git a/src/area/demo/area-simple.js b/src/area/demo/area-simple.ts
similarity index 100%
rename from src/area/demo/area-simple.js
rename to src/area/demo/area-simple.ts
diff --git a/src/area/demo/area.js b/src/area/demo/area.ts
similarity index 100%
rename from src/area/demo/area.js
rename to src/area/demo/area.ts
diff --git a/src/cascader/demo/area-en-US.js b/src/cascader/demo/area-en-US.ts
similarity index 100%
rename from src/cascader/demo/area-en-US.js
rename to src/cascader/demo/area-en-US.ts
diff --git a/src/cascader/demo/area-zh-CN.js b/src/cascader/demo/area-zh-CN.ts
similarity index 100%
rename from src/cascader/demo/area-zh-CN.js
rename to src/cascader/demo/area-zh-CN.ts