feat(button): add new prop dataset

fix #2483

packages/button/README.md

@@ -140,6 +140,7 @@
 | send-message-path | 会话内消息卡片点击跳转小程序路径 | _string_ | 当前分享路径 | - |
 | send-message-img | sendMessageImg | _string_ | 截图 | - |
 | show-message-card | 显示会话内消息卡片 | _string_ | `false` | - |
+| dataset | 按钮 dataset，open-type 为 `share` 时，可在 onShareAppMessage 事件的 `event.target.dataset.data` 中看到传入的值 | _any_ | - | - |
 
 ### Events
 

packages/button/index.ts

@@ -30,6 +30,7 @@ VantComponent({
       type: String,
       value: 'default',
     },
+    dataset: null,
     size: {
       type: String,
       value: 'normal',

packages/button/index.wxml

@@ -2,6 +2,7 @@
 
 <button
   id="{{ id }}"
+  data-data="{{ dataset }}"
   class="custom-class {{ utils.bem('button', [type, size, { block, round, plain, square, loading, disabled, hairline, unclickable: disabled || loading }]) }} {{ hairline ? 'van-hairline--surround' : '' }}"
   hover-class="van-button--active hover-class"
   lang="{{ lang }}"