feat(Stepper): add new prop async-change @rex-zsd (#1133)

example/pages/stepper/index.js

@@ -1,3 +1,8 @@
 import Page from '../../common/page';
+import Toast from '../../dist/toast/toast';
 
-Page();
+Page({
+  onChange(event) {
+    Toast(`change: ${event.detail}`);
+  }
+});

example/pages/stepper/index.wxml

@@ -6,6 +6,15 @@
   <van-stepper value="{{ value1 }}" disabled />
 </demo-block>
 
+<demo-block title="异步变更">
+  <van-stepper
+    value="{{ 5 }}"
+    integer
+    async-change
+    bind:change="onChange"
+  />
+</demo-block>
+
 <demo-block title="高级用法" padding>
   <van-stepper
     value="{{ value2 }}"
@@ -15,3 +24,5 @@
     step="2"
   />
 </demo-block>
+
+<van-toast id="van-toast" />

packages/stepper/README.md

@@ -52,6 +52,7 @@
 | integer | 是否只允许输入整数 | `Boolean` | `false` |
 | disabled | 是否禁用 | `Boolean` | `false` |
 | disable-input | 是否禁用input框 | `Boolean` | `false` |
+| async-change | 异步变更，为 `true` 时input值不变化，仅触发事件 | `Boolean` | `false` |
 
 ### Event
 

packages/stepper/index.ts

@@ -17,6 +17,7 @@ VantComponent({
     value: Number,
     integer: Boolean,
     disabled: Boolean,
+    asyncChange: Boolean,
     disableInput: Boolean,
     min: {
       type: null,
@@ -103,8 +104,10 @@ VantComponent({
       this.onChange('plus');
     },
 
-    triggerInput(value) {
-      this.set({ value });
+    triggerInput(value: string) {
+      this.set({
+        value: this.data.asyncChange ? this.data.value : value
+      });
       this.$emit('change', value);
     }
   }