angular2 patchvalue format with pipes

问题:

how can i use the value format with form contoller patchvalue ?

when i use the ngModel i use value format like this

[ngModel]="policyModel?.amendmentDate | date : 'yyyy-MM-dd'"

now i remove the ngModel and use the formcontroller and use the patchvalue to set values

 this.policyForm
            .patchValue({

            AmendmentDate: this.policyModel.amendmentDate, 
  })

so how can i format this date - amendmentDate