Ionic4 ion-datetime cannot cancel value when using with pickerOptions

Ionic Framework
1

I am using ion-datetime with pickerOptions.
I want to display original datetime value when the user select ‘Cancel’, but I cannot.

Can anybody please help me?

sample on stackblitz

 <ion-datetime [value]="value" [pickerOptions]="customPickerOptions"></ion-datetime>

  value = "2019-09-19 10:00:00";
  customPickerOptions = {
    buttons: [
      {
        text: 'OK',
        handler: ev => {
          console.log(ev);
        }
      },
      {
        text: 'Cancel',
        role: 'cancel',
        handler: () => {
          // I want to set initial datetime here
          // when the picker is cancelled.
          console.log('cancelled');
          this.value = "2019-09-19 10:00:00";
        }
      }
    ]
  };