I have problem with ion-datetime

Ionic Framework ionic-v3
1

I have problem i try set the default date is today . But when i set the default date is today i must convert date to string . So i can’t calculator this . Some body help me set the default date is today and calculator date . Thanks for reading my topic ! .
this is my code :

  this.startDate = new Date().toISOString();
        this.minDate = new Date().toISOString();

    <ion-datetime
                displayFormat="MMM DD, YYYY HH:mm"
                [min]="minDate"
                [(ngModel)]="startDate"
                >
            </ion-datetime>
2

retrieve the date and time from iso String and make new date object and perform date functions with it.