fix(datetime): fix ISO format when w/out timezone data

Closes #6608

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

@@ -14,6 +14,7 @@ class E2EPage {
   webkitOpenSourced = '2005-06-17T11:06Z';
   chromeReleased = '2008-09-02';
   leapYearsSummerMonths = '';
+  convertedDate = '';
 
   leapYearsArray = [2020, 2016, 2008, 2004, 2000, 1996];
 
@@ -39,6 +40,10 @@ class E2EPage {
     this.leapYearsSummerMonths = null;
   }
 
+	convertDate() {
+	  this.convertedDate = new Date(this.myDate).toISOString();
+	}
+
 }
 
 

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

@@ -68,6 +68,18 @@
     <code>Leap year, summer months: {{leapYearsSummerMonths}}</code><br>
   </p>
 
-  <button (click)="clearLeapYear()">Clear Leap Years</button>
+  <p>
+    <button (click)="clearLeapYear()">Clear Leap Years</button>
+  </p>
+
+  <ion-item>
+    <ion-label>myDate: {{myDate}}</ion-label>
+    <ion-datetime displayFormat="MMM DD, YYYY HH:mm" [(ngModel)]="myDate"></ion-datetime>
+  </ion-item>
+
+  <p>
+    <button (click)="convertDate()">Convert myDate To Date</button>
+    {{convertedDate}}
+  </p>
 
 </ion-content>

src/util/datetime-util.ts

@@ -352,7 +352,7 @@ export function convertDataToISO(data: DateTimeData): string {
               rtn += '.' + threeDigit(data.millisecond);
             }
 
-            if (data.tzOffset === 0) {
+            if (isBlank(data.tzOffset) || data.tzOffset === 0) {
               // YYYY-MM-DDTHH:mm:SSZ
               rtn += 'Z';
 

src/util/test/datetime-util.spec.ts

@@ -4,6 +4,20 @@ export function run() {
 
 describe('convertDataToISO', () => {
 
+  it('should convert DateTimeData to datetime string, with blank timezone', () => {
+    var data: datetime.DateTimeData = {
+      year: 1994,
+      month: 12,
+      day: 15,
+      hour: 13,
+      minute: 47,
+      second: 20,
+    };
+
+    var str = datetime.convertDataToISO(data);
+    expect(str).toEqual('1994-12-15T13:47:20Z');
+  });
+
   it('should convert DateTimeData to datetime string, +330 tz offset', () => {
     var data: datetime.DateTimeData = {
       year: 1994,