DatePicker: add onPick option, close #2921 (#3681)

* DatePicker: add onPick option, close #2921

* DatePicker: fix typo

examples/docs/en-US/date-picker.md

@@ -269,6 +269,7 @@ Picking a date range is supported.
 | shortcuts | a { text, onClick } object array to set shortcut options, check the table below | object[] | — | — |
 | disabledDate | a function determining if a date is disabled with that date as its parameter. Should return a Boolean | function | — | — |
 | firstDayOfWeek | first day of week | Number | 1 to 7 | 7 |
+| onPick | a callback that triggers when the seleted date is changed. Only for `daterange` and `datetimerange`. | Function({ maxDate, minDate }) | - | - |
 
 ### shortcuts
 | Attribute      | Description          | Type      | Accepted Values       | Default  |

examples/docs/zh-CN/date-picker.md

@@ -303,6 +303,7 @@
 | shortcuts | 设置快捷选项，需要传入 { text, onClick } 对象用法参考 demo 或下表 | Object[] | — | — |
 | disabledDate | 设置禁用状态，参数为当前日期，要求返回 Boolean | Function | — | — |
 | firstDayOfWeek | 周起始日 | Number | 1 到 7 | 7 |
+| onPick | 选中日期后会执行的回调，只有当 `daterange` 或 `datetimerange` 才生效 | Function({ maxDate, minDate }) | - | - |
 
 ### Shortcuts
 | 参数      | 说明          | 类型      | 可选值                           | 默认值  |

packages/date-picker/src/panel/date-range.vue

@@ -377,9 +377,9 @@
         if (this.maxDate === val.maxDate && this.minDate === val.minDate) {
           return;
         }
+        this.onPick && this.onPick(val);
         this.maxDate = val.maxDate;
         this.minDate = val.minDate;
-
         if (!close || this.showTime) return;
         this.handleConfirm();
       },