diff --git a/src/image-preview/ImagePreview.js b/src/image-preview/ImagePreview.js
index 3ed6cd8d3..59a22f176 100644
--- a/src/image-preview/ImagePreview.js
+++ b/src/image-preview/ImagePreview.js
@@ -214,7 +214,8 @@ export default createComponent({
       if (this.zooming && touches.length === 2) {
         const distance = getDistance(touches);
         const scale = (this.startScale * distance) / this.startDistance;
-        this.scale = range(scale, +this.minZoom, +this.maxZoom);
+
+        this.setScale(scale);
       }
     },
 
diff --git a/src/utils/validate/date.ts b/src/utils/validate/date.ts
index 4e43e6889..d06fd6696 100644
--- a/src/utils/validate/date.ts
+++ b/src/utils/validate/date.ts
@@ -1,8 +1,8 @@
 import { isNaN } from './number';
 
-export function isDate(date: Date): boolean {
+export function isDate(val: Date): val is Date {
   return (
-    Object.prototype.toString.call(date) === '[object Date]' &&
-    !isNaN(date.getTime())
+    Object.prototype.toString.call(val) === '[object Date]' &&
+    !isNaN(val.getTime())
   );
 }