primeng p-calendar autofocus
<p-calendar [monthNavigator]="true" [yearNavigator]="true" yearRange="2018:2030" name="fx_Requested_date" [(ngModel)]="model.fx_Requested_date"
inputId="fx_Requested_date" showButtonBar="true" dateFormat="mm/dd/yy" id="fx_Requested_date" ></p-calendar>
typescript code on button click
(<HTMLInputElement>document.getElementById("fx_Requested_date")).focus();