fix #1

package.json

@@ -1,6 +1,6 @@
 {
   "name": "react-photo-view",
-  "version": "0.3.8",
+  "version": "0.3.9",
   "description": "一款精致的 React 的图片预览组件",
   "author": "MinJieLiu",
   "license": "MIT",

src/utils/isMobile.ts

@@ -1,7 +1,11 @@
 /**
  * 是否为移动端设备
  */
-const isMobile: boolean = typeof window !== 'undefined'
-  && window.navigator.userAgent.includes('Mobile');
+const isMobile =
+  (typeof window !== 'undefined' &&
+    window.navigator &&
+    window.navigator.userAgent &&
+    window.navigator.userAgent.includes('Mobile')) ||
+  false;
 
 export default isMobile;