fix(datetime): clear out existing datetime data

Closes #6614

src/components/datetime/test/basic/index.ts

@@ -27,14 +27,18 @@ class E2EPage {
     'l\u00f8r'
   ];
 
-  onChange(ev) {
+  onChange(ev: any) {
     console.log("Changed", ev);
   }
 
-  onCancel(ev) {
+  onCancel(ev: any) {
     console.log("Canceled", ev);
   }
 
+  clearLeapYear() {
+    this.leapYearsSummerMonths = null;
+  }
+
 }
 
 

src/components/datetime/test/basic/main.html

@@ -68,4 +68,6 @@
     <code>Leap year, summer months: {{leapYearsSummerMonths}}</code><br>
   </p>
 
+  <button (click)="clearLeapYear()">Clear Leap Years</button>
+
 </ion-content>

src/components/datetime/test/datetime.spec.ts

@@ -442,6 +442,20 @@ describe('DateTime', () => {
       expect(datetime.getValue()).toEqual({});
     });
 
+    it('should clear out existing value with blank value', () => {
+      datetime.setValue('1994-12-15T13:47:20.789Z');
+      datetime.setValue(null);
+      expect(datetime.getValue()).toEqual({});
+
+      datetime.setValue('1994-12-15T13:47:20.789Z');
+      datetime.setValue(undefined);
+      expect(datetime.getValue()).toEqual({});
+
+      datetime.setValue('1994-12-15T13:47:20.789Z');
+      datetime.setValue('');
+      expect(datetime.getValue()).toEqual({});
+    });
+
     it('should not parse a value with blank value', () => {
       datetime.setValue(null);
       expect(datetime.getValue()).toEqual({});