Fix：3993 【商城小程序】在多规格商品入口图点击购物车按钮，会保留上一个商品的选择数量

components/ProductWindow.vue

@@ -130,12 +130,23 @@ export default {
     }
   },
   watch: {
+    'attr.cartAttr': {
+      handler(val) {
+        console.log(val);
+        if(!val) {
+          this.cartNumber = 1
+        }
+      },
+      deep: true,
+      immediate: true
+    },
     cartNum: {
       handler(val) {
         console.log(val, 'cardNum');
         this.cartNumber = val || 1
       },
-      deep: true
+      deep: true,
+      immediate: true
     },
     cartNumber(val) {
       if (val > this.attrObj.productSelect.stock) {