validating ionic5 datetime code example
Example 1: ion-datetime min date today
myDate: String = new Date().toISOString();
...
<ion-datetime displayFormat="YYYY-MM-DD" [(ngModel)]="myDate"></ion-datetime>
Example 2: ion datetime interval 30 minutes
<ion-datetime displayFormat="HH:mm" [(ngModel)]="myDate" minuteValues="0,30">