Add start-date prop to force placing of date picker in date

src/components/date-picker/panel/Date/date-panel-mixin.js

@@ -35,6 +35,9 @@ export default {
         value: {
             type: Array,
             default: () => [initTimeDate(), initTimeDate()]
+        },
+        startDate: {
+            type: Date
         }
     },
     computed: {

src/components/date-picker/panel/Date/date-range.vue

@@ -129,14 +129,16 @@
         },
         data(){
             const [minDate, maxDate] = this.value.map(date => date || initTimeDate());
+            const leftPanelDate = this.startDate ? this.startDate : minDate;
+
             return {
                 prefixCls: prefixCls,
                 datePrefixCls: datePrefixCls,
                 dates: this.value,
                 rangeState: {from: this.value[0], to: this.value[1], selecting: minDate && !maxDate},
                 currentView: this.selectionMode || 'range',
-                leftPanelDate: minDate,
-                rightPanelDate: new Date(minDate.getFullYear(), minDate.getMonth() + 1, minDate.getDate())
+                leftPanelDate: leftPanelDate,
+                rightPanelDate: new Date(leftPanelDate.getFullYear(), leftPanelDate.getMonth() + 1, leftPanelDate.getDate())
             };
         },
         computed: {

src/components/date-picker/panel/Date/date.vue

@@ -97,7 +97,7 @@
                 datePrefixCls: datePrefixCls,
                 currentView: this.selectionMode || 'date',
                 dates: dates,
-                panelDate: dates[0] || new Date()
+                panelDate: this.startDate || dates[0] || new Date()
             };
         },
         computed: {

src/components/date-picker/picker.vue

@@ -39,6 +39,7 @@
                         :steps="steps"
                         :format="format"
                         :value="internalValue"
+                        :start-date="startDate"
 
                         v-bind="ownPickerProps"
 
@@ -204,6 +205,9 @@
                 type: Boolean,
                 default: false
             },
+            startDate: {
+                type: Date
+            },
             size: {
                 validator (value) {
                     return oneOf(value, ['small', 'large', 'default']);