block non number directive in Angular 2

Question

Could be this the best angular 2-way to block non number keys using directive?

import {Directive,HostListener} from '@angular/core';

@Directive({
    selector: '[blockNonNumber]'
})

export class blockNonNumberDirective {

    @HostListener('keydown', ['$event']) onKeyDown(event: any) {
        let keyCode = [8, 9, 37, 39, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 110];
        if ( keyCode.indexOf(event.which) === -1) event.preventDefault();
    }
}

Answer 1

I am using this to allow user to enter num only,

export class blockNonNumberDirective {
  constructor() { }

  @HostListener('keypress') onkeypress(e){
    let event = e || window.event;
    if(event){
      return this.isNumberKey(event);
    }
  }

  isNumberKey(event){
     let charCode = (event.which) ? event.which : event.keyCode;
     if (charCode > 31 && (charCode < 48 || charCode > 57)){
        return false;
     }
     return true;
  }
}