time = new Date();
  timeEntered1 = new Date();
  getTime() {
    console.log(this.timeEntered1);
    console.log(this.time);
    console.log(this.timeEntered1.getTime());
    console.log(this.time.getTime());
  }
for console.log(this.time.getTime()); I got an error which "is TypeError: this.timeEntered1.getTime is not a function".
time is a simple Date() variable and timeEntered1 is a Date() which the user enter in my html code, and I got it using two way binding. So I do not get why I can use .getTime with time and why I can not with timeEntered1 since they are both a Date(). 
Here is my html code
  <ion-content padding>
    <ion-datetime  
    displayFormat="HH:mm" 
    [(ngModel)]='timeEntered1' 
    picker-format="HH:mm" 
    >
    Choose time: </ion-datetime>
      <ion-button (click)="getTime()">Pick Time</ion-button>
  </ion-content>
 
    