[new feature] Popup: add opened/closed event (#2650)

packages/popup/en-US.md

@@ -55,5 +55,7 @@ Use `position` prop to set popup display position
 | Event | Description | Arguments |
 |------|------|------|
 | open | Triggered when open Popup | - |
+| opened | Triggered when opened Popup | - |
 | close | Triggered when close Popup | - |
+| closed | Triggered when closed Popup | - |
 | click-overlay | Triggered when click overlay | - |

packages/popup/index.js

@@ -25,10 +25,15 @@ export default sfc({
     }
 
     const { position } = this;
+    const emit = event => () => this.$emit(event);
     const transitionName = this.transition || (position ? `van-popup-slide-${position}` : 'van-fade');
 
     return (
-      <transition name={transitionName}>
+      <transition
+        name={transitionName}
+        onAfterEnter={emit('opened')}
+        onAfterLeave={emit('closed')}
+      >
         <div vShow={this.value} class={bem({ [position]: position })}>
           {this.$slots.default}
         </div>

packages/popup/zh-CN.md

@@ -55,5 +55,7 @@ export default {
 | 事件名 | 说明 | 参数 |
 |------|------|------|
 | open | 打开弹出层时触发 | - |
+| opened | 打开弹出层且动画结束后触发 | - |
 | close | 关闭弹出层时触发 | - |
+| closed | 关闭弹出层且动画结束后触发 | - |
 | click-overlay | 点击蒙层时触发 | - |