图片预览组件实例懒加载

src/image/preview.js

@@ -262,15 +262,21 @@ class ImagePreview extends Component {
   }
 }
 ImagePreview.reg('image-preview')
-const instance = new ImagePreview()
-document.body.appendChild(instance)
+
+let instance = null
 
 window.imagePreview = function (options) {
+  if (!instance) {
+    instance = new ImagePreview()
+    document.body.appendChild(instance)
+  }
+
   if (Array.isArray(options)) {
     instance.list = options
   } else {
     Object.assign(instance, options)
   }
+
   instance.visible = true
   return instance
 }