fix(DateTimePicker): fix incorrecrt inital value (#8193)

src/datetime-picker/DatePicker.tsx

@@ -60,7 +60,8 @@ export default createComponent({
         );
         return new Date(timestamp);
       }
-      return props.minDate;
+      
+      return undefined;
     };
 
     const picker = ref<ComponentInstance>();
@@ -106,12 +107,12 @@ export default createComponent({
     const ranges = computed(() => {
       const { maxYear, maxDate, maxMonth, maxHour, maxMinute } = getBoundary(
         'max',
-        currentDate.value
+        currentDate.value || props.minDate
       );
 
       const { minYear, minDate, minMonth, minHour, minMinute } = getBoundary(
         'min',
-        currentDate.value
+        currentDate.value || props.minDate
       );
 
       let result: Array<{ type: ColumnType; range: number[] }> = [
@@ -191,7 +192,7 @@ export default createComponent({
     );
 
     const updateColumnValue = () => {
-      const { value } = currentDate;
+      const value = currentDate.value || props.minDate;
       const { formatter } = props;
 
       const values = originColumns.value.map((column) => {
@@ -236,7 +237,7 @@ export default createComponent({
       let month;
       let day;
       if (type === 'month-day') {
-        year = currentDate.value.getFullYear();
+        year = (currentDate.value || props.minDate).getFullYear();
         month = getValue('month');
         day = getValue('day');
       } else {
@@ -265,6 +266,7 @@ export default createComponent({
     };
 
     const onConfirm = () => {
+      emit('update:modelValue', currentDate.value);
       emit('confirm', currentDate.value);
     };
 
@@ -288,8 +290,8 @@ export default createComponent({
 
     watch(columns, updateColumnValue);
 
-    watch(currentDate, (value) => {
+    watch(currentDate, (value, oldValue) => {
-      emit('update:modelValue', value);
+      emit('update:modelValue', oldValue ? value : null);
     });
 
     watch(
@@ -302,7 +304,7 @@ export default createComponent({
       (value) => {
         value = formatValue(value);
 
-        if (value.valueOf() !== currentDate.value.valueOf()) {
+        if (value && value.valueOf() !== currentDate.value?.valueOf()) {
           currentDate.value = value;
         }
       }

src/datetime-picker/test/index.spec.js

@@ -0,0 +1,59 @@
+import {later, mount, triggerDrag} from "../../../test"
+import DatePicker from "../DatePicker"
+
+test('month-day type', async () => {
+  const date = new Date(2020, 10, 1, 0, 0);
+
+  const wrapper = mount(DatePicker, {
+    props: {
+      type: 'month-day',
+      modelValue: date,
+      minDate: new Date(2020, 0, 1),
+      maxDate: new Date(2025, 10, 1),
+    },
+  });
+
+  await later();
+  wrapper.find('.van-picker__confirm').trigger('click');
+  expect(wrapper.emitted('confirm')[0][0].getMonth()).toEqual(10);
+  expect(wrapper.emitted('confirm')[0][0].getDate()).toEqual(1);
+
+  await later();
+  triggerDrag(wrapper.find('.van-picker-column'), 0, -300);
+  wrapper.find('.van-picker__confirm').trigger('click');
+  expect(wrapper.emitted('confirm')[1][0].getMonth()).toEqual(11);
+  expect(wrapper.emitted('confirm')[1][0].getDate()).toEqual(1);
+
+  await later();
+  triggerDrag(wrapper.findAll('.van-picker-column')[1], 0, -300);
+  wrapper.find('.van-picker__confirm').trigger('click');
+  expect(wrapper.emitted('confirm')[2][0].getMonth()).toEqual(11);
+  expect(wrapper.emitted('confirm')[2][0].getDate()).toEqual(31);
+});
+
+test('v-model', async () => {
+  const minDate = new Date(2030, 0, 0, 0, 3);
+
+  const wrapper = mount(DatePicker, {
+    props: {
+      minDate,
+    }
+  })
+  
+  await later();
+  wrapper.find('.van-picker__confirm').trigger('click');
+  expect(wrapper.emitted('confirm')[0][0]).toEqual(minDate);
+});
+
+test('value has an inital value', async () => {
+  const defaultValue = new Date(2020, 0, 0, 0, 0);
+  const wrapper = mount(DatePicker, {
+    propsData: {
+      modelValue: defaultValue,
+    },
+  });
+
+  await later();
+  wrapper.find('.van-picker__confirm').trigger('click');
+  expect(wrapper.emitted('confirm')[0][0]).toEqual(defaultValue);
+});