Card 组件增加 centered 属性 (#54)

docs/examples-docs/card.md

@@ -77,6 +77,7 @@ export default {
 | thumb | 左侧图片 | `string`  |          |          |
 | title | 标题 | `string`  |          |          |
 | desc | 描述 | `string`  |          |          |
+| centered | 内容是否垂直居中 | `string`  | `false` |          |
 
 
 ### Slot

packages/card/src/card.vue

@@ -1,5 +1,5 @@
 <template>
-  <div :class="['van-card', { 'van-card--center': !$slots.footer }]">
+  <div :class="['van-card', { 'van-card--center': centered }]">
     <div class="van-card__thumb">
       <slot name="thumb">
         <img :src="thumb" class="van-card__img" />
@@ -21,10 +21,12 @@
 <script>
 export default {
   name: 'van-card',
+
   props: {
     thumb: String,
     title: String,
-    desc: String
+    desc: String,
+    centered: Boolean
   }
 };
 </script>