feat: add calendar-change event (#432)

Author: mengxiong10

README.md

@@ -266,18 +266,19 @@ set fixed time list to select;
 
 ### Events
 
-| Name        | Description                          | Callback Arguments                           |
-| ----------- | ------------------------------------ | -------------------------------------------- |
-| input       | When the value change(v-model event) | date                                         |
-| change      | When the value change(same as input) | date, type(date, hour, minute, second, ampm) |
-| open        | When panel opening                   |                                              |
-| close       | When panel closing                   |                                              |
-| confirm     | When click 'confirm' button          | date                                         |
-| clear       | When click 'clear' button            |                                              |
-| input-error | When user type a invalid Date        | the input text                               |
-| focus       | When input focus                     |                                              |
-| blur        | When input blur                      |                                              |
-| pick        | when select date [#429](issues/429)  | date                                         |
+| Name            | Description                          | Callback Arguments                           |
+| --------------- | ------------------------------------ | -------------------------------------------- |
+| input           | When the value change(v-model event) | date                                         |
+| change          | When the value change(same as input) | date, type(date, hour, minute, second, ampm) |
+| open            | When panel opening                   |                                              |
+| close           | When panel closing                   |                                              |
+| confirm         | When click 'confirm' button          | date                                         |
+| clear           | When click 'clear' button            |                                              |
+| input-error     | When user type a invalid Date        | the input text                               |
+| focus           | When input focus                     |                                              |
+| blur            | When input blur                      |                                              |
+| pick            | when select date [#429](issues/429)  | date                                         |
+| calendar-change | when change the calendar             | date, oldDate                                |
 
 ### Slots
 

README.zh-CN.md

@@ -263,18 +263,19 @@ data() {
 
 ### 事件
 
-| 名称        | 描述                            | 回调函数的参数                               |
-| ----------- | ------------------------------- | -------------------------------------------- |
-| input       | 当选择日期的事件触发            | date                                         |
-| change      | 当选择日期的事件触发            | date, type(date, hour, minute, second, ampm) |
-| open        | 当弹出层打开时候                |                                              |
-| close       | 当弹出层关闭时候                |                                              |
-| confirm     | 当点击确认按钮                  | date                                         |
-| clear       | 当点击清除按钮                  |                                              |
-| input-error | 当输入一个无效的时间            | 输入的值                                     |
-| focus       | 当输入框有焦点                  |                                              |
-| blur        | 当输入框失焦                    |                                              |
-| pick        | 当点击日期时 [#429](issues/429) | date                                         |
+| 名称            | 描述                            | 回调函数的参数                               |
+| --------------- | ------------------------------- | -------------------------------------------- |
+| input           | 当选择日期的事件触发            | date                                         |
+| change          | 当选择日期的事件触发            | date, type(date, hour, minute, second, ampm) |
+| open            | 当弹出层打开时候                |                                              |
+| close           | 当弹出层关闭时候                |                                              |
+| confirm         | 当点击确认按钮                  | date                                         |
+| clear           | 当点击清除按钮                  |                                              |
+| input-error     | 当输入一个无效的时间            | 输入的值                                     |
+| focus           | 当输入框有焦点                  |                                              |
+| blur            | 当输入框失焦                    |                                              |
+| pick            | 当点击日期时 [#429](issues/429) | date                                         |
+| calendar-change | 当改变年月时                    | date, oldDate                                |
 
 ### Slots
 

src/calendar/calendar-panel.vue

@@ -255,8 +255,10 @@ export default {
       }
     },
     updateCalendar(date) {
+      const oldValue = new Date(this.innerCalendar);
       this.innerCalendar = date;
       this.$emit('update:calendar', date);
+      this.dispatch('DatePicker', 'calendar-change', date, oldValue);
     },
     handelPanelChange(panel) {
       this.panel = panel;