[new feature] Checkbox: support config the maximum amount of checked options (#631)

docs/demos/views/checkbox.vue

@@ -30,6 +30,16 @@
         </van-cell-group>
       </van-checkbox-group>
     </demo-block>
+
+    <demo-block :title="$t('title5')">
+      <van-checkbox-group v-model="result" :max="max">
+        <van-cell-group>
+          <van-cell v-for="(item, index) in list" :key="index">
+            <van-checkbox :name="item">{{ $t('checkbox') }} {{ item }}</van-checkbox>
+          </van-cell>
+        </van-cell-group>
+      </van-checkbox-group>
+    </demo-block>
   </demo-section>
 </template>
 
@@ -39,12 +49,14 @@ export default {
     'zh-CN': {
       checkbox: '复选框',
       title3: 'Checkbox 组',
-      title4: '与 Cell 组件一起使用'
+      title4: '与 Cell 组件一起使用',
+      title5: '设置最大可选数',
     },
     'en-US': {
       checkbox: 'Checkbox',
       title3: 'Checkbox Group',
-      title4: 'Inside a Cell'
+      title4: 'Inside a Cell',
+      title5: 'Configure the maximum amount of checked options'
     }
   },
 
@@ -57,7 +69,8 @@ export default {
         'b',
         'c'
       ],
-      result: ['a', 'b']
+      result: ['a', 'b'],
+      max: 2
     };
   }
 };

docs/markdown/en-US/checkbox.md

@@ -69,6 +69,30 @@ export default {
 </van-checkbox-group>
 ```
 
+#### Configure the maximum amount of checked options
+
+```html
+<van-checkbox-group v-model="result" :max="max">
+  <van-cell-group>
+    <van-cell v-for="(item, index) in list" :key="index">
+      <van-checkbox :name="item">Checkbox {{ item }}</van-checkbox>
+    </van-cell>
+  </van-cell-group>
+</van-checkbox-group>
+```
+
+```
+export default {
+  data() {
+    return {
+      list: ['a', 'b', 'c'],
+      result: ['a', 'b'],
+      max: 2
+    };
+  }
+};
+```
+
 ### Checkbox API
 
 | Attribute | Description | Type | Default | Accepted Values |
@@ -82,6 +106,7 @@ export default {
 | Attribute | Description | Type | Default | Accepted Values |
 |-----------|-----------|-----------|-------------|-------------|
 | disabled | Disable all checkboxes | `Boolean` | `false` | - |
+| max | the maximum amount of checked options | `Number` | `0`(Unlimited) | - |
 
 ### Checkbox Event
 

docs/markdown/zh-CN/checkbox.md

@@ -73,6 +73,33 @@ export default {
 </van-checkbox-group>
 ```
 
+#### 设置最大可选数
+
+此时你需要引入`CellGroup`组件，`Cell`组件非必须
+
+```html
+<van-checkbox-group v-model="result" :max="max">
+  <van-cell-group>
+    <van-cell v-for="(item, index) in list" :key="index">
+      <van-checkbox :name="item">复选框 {{ item }}</van-checkbox>
+    </van-cell>
+  </van-cell-group>
+</van-checkbox-group>
+```
+
+```
+export default {
+  data() {
+    return {
+      list: ['a', 'b', 'c'],
+      result: ['a', 'b'],
+      max: 2
+    };
+  }
+};
+```
+
+
 ### Checkbox API
 
 | 参数 | 说明 | 类型 | 默认值 | 可选值 |
@@ -86,6 +113,7 @@ export default {
 | 参数 | 说明 | 类型 | 默认值 | 可选值 |
 |-----------|-----------|-----------|-------------|-------------|
 | disabled | 是否禁用所有单选框 | `Boolean` | `false` | - |
+| max | 设置最大可选数 | `Number` | `0`（无限制） | - |
 
 ### Checkbox Event