[new feature] Button: add loading-text prop (#1300)

example/pages/button/index.wxml

@@ -19,8 +19,8 @@
   </demo-block>
 
   <demo-block title="加载状态" padding>
-    <van-button loading type="primary" class="demo-margin-right" loading-class="loading" />
-    <van-button loading type="danger" loading-class="loading" />
+    <van-button loading type="primary" class="demo-margin-right" />
+    <van-button loading type="danger" loading-text="加载中..." />
   </demo-block>
 
   <demo-block title="按钮形状" padding>

example/pages/button/index.wxss

@@ -1,7 +1,3 @@
-.loading {
-  margin: 0 18px;
-}
-
 .row {
   height: 44px;
   margin-bottom: 15px;

packages/button/README.md

@@ -40,7 +40,7 @@
 
 ```html 
 <van-button loading type="primary" />
-<van-button loading type="danger" />
+<van-button loading type="danger" loading-text="加载中..." />
 ```
 
 #### 按钮形状

packages/button/index.less

@@ -125,4 +125,10 @@
   &--disabled {
     opacity: 0.5;
   }
+
+  &__loading-text {
+    margin-left: 5px;
+    display: inline-block;
+    vertical-align: middle;
+  }
 }

packages/button/index.ts

@@ -14,6 +14,7 @@ VantComponent({
     square: Boolean,
     loading: Boolean,
     disabled: Boolean,
+    loadingText: String,
     type: {
       type: String,
       value: 'default'

packages/button/index.wxml

@@ -23,11 +23,18 @@
   bindlaunchapp="bindLaunchApp"
   bindopensetting="bindOpenSetting"
 >
-  <van-loading
-    wx:if="{{ loading }}"
-    custom-class="loading-class"
-    size="{{ size === 'mini' ? '14px' : '20px' }}"
-    color="{{ type === 'default' ? '#c9c9c9' : '' }}"
-  />
+  <block wx:if="{{ loading }}">
+    <van-loading
+      custom-class="loading-class"
+      size="{{ size === 'mini' ? '14px' : '20px' }}"
+      color="{{ type === 'default' ? '#c9c9c9' : '' }}"
+    />
+    <view
+      wx:if="{{ loadingText }}"
+      class="van-button__loading-text"
+    >
+      {{ loadingText }}
+    </view>
+  </block>
   <slot wx:else />
 </button>