ngx-mask Do not allow negative value for the currency input

Update on 01.09.2020

I have created the directive for blocking the type of negative(-) values.

Here is the directive example.

import { Directive, ElementRef, OnInit, OnDestroy } from "@angular/core";
import { fromEvent } from "rxjs/internal/observable/fromEvent";
import { Subscription } from "rxjs";

@Directive({
  // tslint:disable-next-line: directive-selector
  selector: "[onlyPositive]"
})
export class OnlyPositiveDirective implements OnInit, OnDestroy {
  subscriber$: Subscription;

  constructor(private element: ElementRef<HTMLInputElement>) {}

  ngOnInit() {
    const input = this.element.nativeElement;
    this.subscriber$ = fromEvent(input, 'input').subscribe(
      (event: KeyboardEvent) => {
        if (input.value.includes('-')) {
          input.value = input.value.replace(/-/g, '');
        }
      }
    );
  }

  ngOnDestroy() {
    this.subscriber$.unsubscribe();
  }
}

Usage example

<input onlyPositive mask="separator.2" thousandSeparator="," separatorLimit="99999999" [allowNegativeNumbers]="false" placeholder="Currency">

After Adams Advice I have changed the keypress event to the input event

DEMO: https://stackblitz.com/edit/ngx-mask-currency-input?file=src/app/app.component.html