feat(Calendar): scroll to current month when show (#5526)

src/calendar/index.js

@@ -117,6 +117,7 @@ export default createComponent({
     value(val) {
       if (val) {
         this.initRect();
+        this.scrollIntoView();
       }
     },
 
@@ -126,7 +127,7 @@ export default createComponent({
   },
 
   mounted() {
-    if (!this.poppable) {
+    if (this.value || !this.poppable) {
       this.initRect();
     }
   },
@@ -144,6 +145,28 @@ export default createComponent({
       });
     },
 
+    // scroll to current month
+    scrollIntoView() {
+      this.$nextTick(() => {
+        const { type, currentDate } = this;
+        const targetDate = type === 'range' ? currentDate[0] : currentDate;
+
+        /* istanbul ignore if */
+        if (!targetDate) {
+          return;
+        }
+
+        this.months.some((month, index) => {
+          if (compareMonth(month, targetDate) === 0) {
+            this.$refs.months[index].$el.scrollIntoView();
+            return true;
+          }
+
+          return false;
+        });
+      });
+    },
+
     getInitialDate() {
       const { type, defaultDate, minDate } = this;
 

src/calendar/test/index.spec.js

@@ -407,3 +407,23 @@ test('color prop when type is range', async () => {
 
   expect(wrapper).toMatchSnapshot();
 });
+
+test('should scroll to current month when show', async done => {
+  const wrapper = mount(Calendar, {
+    propsData: {
+      type: 'range',
+      minDate: new Date(2010, 0, 10),
+      maxDate: new Date(2010, 11, 10),
+      defaultDate: [new Date(2010, 3, 1), new Date(2010, 5, 1)]
+    }
+  });
+
+  Element.prototype.scrollIntoView = function() {
+    expect(this).toEqual(wrapper.findAll('.van-calendar__month').at(3).element);
+    done();
+  };
+
+  wrapper.setProps({ value: true });
+
+  await later();
+});

test/dom.ts

@@ -30,6 +30,11 @@ function mockHTMLElementOffset() {
   });
 }
 
+function mockScrollIntoView() {
+  Element.prototype.scrollIntoView = function() {};
+}
+
+mockScrollIntoView();
 mockHTMLElementOffset();
 
 export function mockGetBoundingClientRect(